💚 fix build

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

.cirrus.yml

@@ -3,15 +3,15 @@ arm_container:
 
 check_task:
   check_script:
-  - wget https://github.com/Kitware/CMake/releases/download/v3.20.2/cmake-3.20.2.tar.gz
-  - tar xfz cmake-3.20.2.tar.gz
-  - cd cmake-3.20.2
-  - ./configure
-  - make cmake ctest -j4
-  - cd ..
+  # the gcc image ships an outdated CMake, so fetch a recent prebuilt binary
+  # instead of compiling CMake from source
+  - wget -q https://github.com/Kitware/CMake/releases/download/v4.3.4/cmake-4.3.4-linux-aarch64.tar.gz
+  - tar xfz cmake-4.3.4-linux-aarch64.tar.gz
+  - export PATH="$(pwd)/cmake-4.3.4-linux-aarch64/bin:$PATH"
+  - cmake --version
   - mkdir build
   - cd build
-  - ../cmake-3.20.2/bin/cmake .. -DJSON_FastTests=ON
+  - cmake .. -DJSON_FastTests=ON
   - make -j4
   - cd tests
-  - ../../cmake-3.20.2/bin/ctest -j4
+  - ctest -j4

.clang-tidy

@@ -1,4 +1,5 @@
 # TODO: The first three checks are only removed to get the CI going. They have to be addressed at some point.
+# TODO: portability-avoid-pragma-once: should be fixed eventually
 
 Checks: '*,
 
@@ -21,6 +22,7 @@ Checks: '*,
          -cppcoreguidelines-avoid-magic-numbers,
          -cppcoreguidelines-avoid-non-const-global-variables,
          -cppcoreguidelines-macro-usage,
+         -cppcoreguidelines-pro-bounds-avoid-unchecked-container-access,
          -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
          -cppcoreguidelines-pro-bounds-constant-array-index,
          -cppcoreguidelines-pro-bounds-pointer-arithmetic,
@@ -33,6 +35,7 @@ Checks: '*,
          -fuchsia-overloaded-operator,
          -google-explicit-constructor,
          -google-readability-function-size,
+         -google-runtime-float,
          -google-runtime-int,
          -google-runtime-references,
          -hicpp-avoid-goto,
@@ -44,6 +47,8 @@ Checks: '*,
          -hicpp-uppercase-literal-suffix,
          -llvm-header-guard,
          -llvm-include-order,
+         -llvm-prefer-static-over-anonymous-namespace,
+         -llvm-use-ranges,
          -llvmlibc-*,
          -misc-use-anonymous-namespace,
          -misc-confusable-identifiers,
@@ -59,13 +64,16 @@ Checks: '*,
          -modernize-use-std-numbers,
          -modernize-use-trailing-return-type,
          -performance-enum-size,
+         -portability-avoid-pragma-once,
          -readability-function-cognitive-complexity,
          -readability-function-size,
          -readability-identifier-length,
          -readability-magic-numbers,
          -readability-redundant-access-specifiers,
+         -readability-redundant-parentheses,
          -readability-simplify-boolean-expr,
-         -readability-uppercase-literal-suffix'
+         -readability-uppercase-literal-suffix,
+         -readability-use-concise-preprocessor-directives'
 
 CheckOptions:
   - key: hicpp-special-member-functions.AllowSoleDefaultDtor

.github/CONTRIBUTING.md

@@ -1,7 +1,7 @@
 # Contribution Guidelines
 
 Thank you for your interest in contributing to this project! What began as an exercise to explore the exciting features
-of C++11 has evolved into a [widely-used](https://json.nlohmann.me/home/customers/) JSON library. I truly appreciate all
+of C++11 has evolved into a [widely used](https://json.nlohmann.me/home/customers/) JSON library. I truly appreciate all
 the contributions from the community, whether it's proposing features, identifying bugs, or fixing mistakes! To ensure
 that our collaboration is efficient and effective, please follow these guidelines.
 
@@ -21,7 +21,7 @@ Clearly describe the issue:
 
 - If it is a bug, please describe how to **reproduce** it. If possible, attach a _complete example_ which demonstrates
   the error. Please also state what you **expected** to happen instead of the error.
-- If you propose a change or addition, try to give an **example** how the improved code could look like or how to use
+- If you propose a change or addition, try to give an **example** what the improved code could look like or how to use
   it.
 - If you found a compilation error, please tell us which **compiler** (version and operating system) you used and paste
   the (relevant part of) the error messages to the ticket.
@@ -66,21 +66,21 @@ certification that he or she has the right to submit the patch for inclusion int
 
 ### Describe your changes
 
-This library is primarily maintained as a spare-time project. As such, I can not make any guarantee how quickly changes
+This library is primarily maintained as a spare-time project. As such, I cannot make any guarantee how quickly changes
 are merged and released. Therefore, it is very important to make the review as smooth as possible by explaining not only
 _what_ you changed, but _why_. This rationale can be very valuable down the road when improvements or bugs are discussed
 years later.
 
-### Reference existing issues
+### Reference an existing issue
 
 [Link a pull request to an issue](https://docs.github.com/en/issues/tracking-your-work-with-issues/using-issues/linking-a-pull-request-to-an-issue)
-to clarify that a fix is forthcoming and which issue can be closed after merging. Only few cases (e.g., fixing typos)
-don’t require prior discussions.
+to clarify that a fix is forthcoming and which issue can be closed after merging. Only a few cases (e.g., fixing typos)
+do not require prior discussions.
 
 ### Write tests
 
 The library has an extensive test suite that currently covers [100 %](https://coveralls.io/github/nlohmann/json) of the
-library's code. These test are crucial to maintain API stability and give future contributors confidence that they do
+library's code. These tests are crucial to maintain API stability and give future contributors confidence that they do
 not accidentally break things. As Titus Winters aptly put it:
 
 > If you liked it, you should have put a test on it.
@@ -118,14 +118,14 @@ exception into account.
 #### Coverage
 
 If test coverage decreases, an automatic warning comment will be posted on the pull request. You can access a code
-coverage report as artifact to the “Ubuntu” workflow.
+coverage report as an artifact to the “Ubuntu” workflow.
 
 ### Update the documentation
 
 The [main documentation](https://json.nlohmann.me) of the library is generated from the files
 [`docs/mkdocs/docs`](https://github.com/nlohmann/json/blob/develop/docs/mkdocs/docs). This folder contains dedicated
 pages for [certain features](https://github.com/nlohmann/json/tree/develop/docs/mkdocs/docs/features), a list of
-[all exceptions](https://github.com/nlohmann/json/blob/develop/docs/mkdocs/docs/home/exceptions.md), and an
+[all exceptions](https://github.com/nlohmann/json/blob/develop/docs/mkdocs/docs/home/exceptions.md), and 
 [extensive API documentation](https://github.com/nlohmann/json/tree/develop/docs/mkdocs/docs/api) with details on every
 public API function.
 
@@ -136,7 +136,7 @@ make install_venv -C docs/mkdocs
 make serve -C docs/mkdocs
 ```
 
-The documentation will then available at <http://127.0.0.1:8000/>. See the documentation of
+The documentation will then be available at <http://127.0.0.1:8000/>. See the documentation of
 [mkdocs](https://www.mkdocs.org) and [Material for MkDocs](https://squidfunk.github.io/mkdocs-material/) for more
 information.
 
@@ -153,6 +153,9 @@ files directly; instead, modify the include/nlohmann sources and regenerate the
 make amalgamate
 ```
 
+Running `make amalgamate` will also apply automatic formatting to the source files using
+[`Artistic Style`](https://astyle.sourceforge.net/). This formatting may modify your source files in-place. Be certain to review and commit any changes to avoid unintended formatting diffs in commits.
+
 ## Recommended documentation
 
 - The library’s [README file](https://github.com/nlohmann/json/blob/master/README.md) is an excellent starting point to
@@ -184,8 +187,8 @@ API of the 3.x.y version is broken. This includes:
 Although these guidelines may seem restrictive, they are essential for maintaining the library’s utility.
 
 Breaking changes may be introduced when they are guarded with a feature macro such as
-[`JSON_USE_IMPLICIT_CONVERSIONS`](https://json.nlohmann.me/api/macros/json_use_implicit_conversions/) which allows to
-selectively change the behavior of the library. In next steps, the current behavior can then be deprecated. Using
+[`JSON_USE_IMPLICIT_CONVERSIONS`](https://json.nlohmann.me/api/macros/json_use_implicit_conversions/) which allows 
+selectively changing the behavior of the library. In next steps, the current behavior can then be deprecated. Using
 feature macros then allows users to test their code against the library in the next major release.
 
 ### Break C++11 language conformance
@@ -211,7 +214,7 @@ The following areas really need contribution and are always welcomed:
 - Extending the **continuous integration** toward more exotic compilers such as Android NDK, Intel's Compiler, or the
   bleeding-edge versions Clang.
 - Improving the efficiency of the **JSON parser**. The current parser is implemented as a naive recursive descent parser
-  with hand coded string handling. More sophisticated approaches like LALR parsers would be really appreciated. That
+  with hand-coded string handling. More sophisticated approaches like LALR parsers would be really appreciated. That
   said, parser generators like Bison or ANTLR do not play nice with single-header files -- I really would like to keep
   the parser inside the `json.hpp` header, and I am not aware of approaches similar to [`re2c`](http://re2c.org) for
   parsing.

.github/ISSUE_TEMPLATE/bug.yaml

@@ -14,6 +14,8 @@ body:
         Note that this form is for bug reports only. Please
         [open a discussion](https://github.com/nlohmann/json/discussions/new)
         for questions, feature requests, or support requests.
+        **Please check the [FAQ](https://json.nlohmann.me/home/faq/) before
+        reporting an issue.** Common questions are answered there.        
   - type: textarea
     id: summary
     attributes:

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,4 +1,4 @@
-[Describe your pull request here. Please read the text below the line, and make sure you follow the checklist.]
+[Describe your pull request here. Please read the text below the line and make sure you follow the checklist.]
 
 - [ ] The changes are described in detail, both the what and why.
 - [ ] If applicable, an [existing issue](https://github.com/nlohmann/json/issues) is referenced.

.github/config.yml

@@ -13,7 +13,7 @@ sentimentBotReplyComment: >
 
 # *Required* Comment to reply with
 requestInfoReplyComment: >
-  We would appreciate it if you could provide us with more info about this issue or pull request! Please check the [issue template](https://github.com/nlohmann/json/blob/develop/.github/ISSUE_TEMPLATE.md) and the [pull request template](https://github.com/nlohmann/json/blob/develop/.github/PULL_REQUEST_TEMPLATE.md).
+  We would appreciate it if you could provide us with more info about this issue or pull request! Please check the [issue template](https://github.com/nlohmann/json/issues/new/choose) and the [pull request template](https://github.com/nlohmann/json/blob/develop/.github/PULL_REQUEST_TEMPLATE.md).
 
 # *OPTIONAL* Label to be added to Issues and Pull Requests with insufficient information given
 requestInfoLabelToAdd: "state: needs more info"

.github/labeler.yml

@@ -23,11 +23,11 @@ labels:
 
 - label: "CI"
   files:
-    - "github/workflows/.*"
+    - ".github/workflows/.*"
 
 - label: "CI"
   files:
-    - "github/external_ci/.*"
+    - ".github/external_ci/.*"
 
 - label: "S"
   size-below: 10

.github/workflows/check_amalgamation.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
@@ -20,7 +20,7 @@ jobs:
           mkdir -p ./pr
           echo ${{ github.event.number }} > ./pr/number
           echo ${{ github.event.pull_request.user.login }} > ./pr/author
-      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: pr
           path: pr/
@@ -34,21 +34,23 @@ jobs:
 
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
       - name: Checkout pull request
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           path: main
           ref: ${{ github.event.pull_request.head.sha }}
+          persist-credentials: false
 
       - name: Checkout tools
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           path: tools
           ref: develop
+          persist-credentials: false
 
       - name: Install astyle
         run: |

.github/workflows/cifuzz.yml

@@ -6,29 +6,32 @@ permissions:
 
 jobs:
   Fuzzing:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
     - name: Harden Runner
-      uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+      uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
       with:
         egress-policy: audit
 
+    # The OSS-Fuzz CIFuzz actions are referenced via @master as recommended by
+    # the OSS-Fuzz documentation; the project does not publish tags or releases
+    # to pin to. See https://google.github.io/oss-fuzz/getting-started/continuous-integration/
     - name: Build Fuzzers
       id: build
-      uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@57fe4475324c5506adbfecdcdd2917f65c86ee9e # master
+      uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
       with:
         oss-fuzz-project-name: 'json'
         dry-run: false
         language: c++
     - name: Run Fuzzers
-      uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@57fe4475324c5506adbfecdcdd2917f65c86ee9e # master
+      uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
       with:
         oss-fuzz-project-name: 'json'
         fuzz-seconds: 300
         dry-run: false
         language: c++
     - name: Upload Crash
-      uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+      uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
       if: failure() && steps.build.outcome == 'success'
       with:
         name: artifacts

.github/workflows/codeql-analysis.yml

@@ -27,23 +27,25 @@ jobs:
 
     steps:
     - name: Harden Runner
-      uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+      uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
       with:
         egress-policy: audit
 
     - name: Checkout repository
-      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      with:
+        persist-credentials: false
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@fc7e4a0fa01c3cca5fd6a1fddec5c0740c977aa2 # v3.28.14
+      uses: github/codeql-action/init@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4.36.2
       with:
         languages: c-cpp
 
     # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
     # If this step fails, then you should remove it and run the build manually (see below)
     - name: Autobuild
-      uses: github/codeql-action/autobuild@fc7e4a0fa01c3cca5fd6a1fddec5c0740c977aa2 # v3.28.14
+      uses: github/codeql-action/autobuild@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4.36.2
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@fc7e4a0fa01c3cca5fd6a1fddec5c0740c977aa2 # v3.28.14
+      uses: github/codeql-action/analyze@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4.36.2

.github/workflows/comment_check_amalgamation.yml

@@ -19,12 +19,12 @@ jobs:
       pull-requests: write
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
       - name: 'Download artifact'
-        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           script: |
             var artifacts = await github.rest.actions.listWorkflowRunArtifacts({
@@ -46,7 +46,7 @@ jobs:
       - run: unzip pr.zip
 
       - name: 'Comment on PR'
-        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |

.github/workflows/dependency-review.yml

@@ -17,11 +17,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
       - name: 'Checkout Repository'
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: 'Dependency Review'
-        uses: actions/dependency-review-action@ce3cf9537a52e8119d91fd484ab5b8a807627bf8 # v4.6.0
+        uses: actions/dependency-review-action@a1d282b36b6f3519aa1f3fc636f609c47dddb294 # v5.0.0

.github/workflows/flawfinder.yml

@@ -0,0 +1,48 @@
+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+
+name: flawfinder
+
+permissions:
+  contents: read
+
+on:
+  push:
+    branches: [ "develop" ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ "develop" ]
+  schedule:
+    - cron: '41 14 * * 3'
+
+jobs:
+  flawfinder:
+    name: Flawfinder
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
+        with:
+          egress-policy: audit
+
+      - name: Checkout code
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+
+      - name: flawfinder_scan
+        uses: david-a-wheeler/flawfinder@c4216b74cf2639ffa98503768bd6e4299b5440c9 # v2.0.20
+        with:
+          arguments: '--sarif ./'
+          output: 'flawfinder_results.sarif'
+
+      - name: Upload analysis results to GitHub Security tab
+        uses: github/codeql-action/upload-sarif@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4.36.2
+        with:
+          sarif_file: ${{github.workspace}}/flawfinder_results.sarif

.github/workflows/labeler.yml

@@ -17,10 +17,10 @@ jobs:
 
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
-      - uses: srvaroa/labeler@e216fb40e2e6d3b17d90fb1d950f98bee92f65ce # master
+      - uses: srvaroa/labeler@bf262763a8a8e191f5847873aecc0f29df84f957 # v1.14.0
         env:
           GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"

.github/workflows/macos.yml

@@ -17,69 +17,18 @@ permissions:
   contents: read
 
 jobs:
-# macos-11 is deprecated
-#  macos-11:
-#    runs-on: macos-11
-#    strategy:
-#      matrix:
-#        xcode: ['11.7', '12.4', '12.5.1', '13.0']
-#    env:
-#      DEVELOPER_DIR: /Applications/Xcode_${{ matrix.xcode }}.app/Contents/Developer
-#
-#    steps:
-#      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-#      - name: Run CMake
-#        run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DJSON_FastTests=ON
-#      - name: Build
-#        run: cmake --build build --parallel 10
-#      - name: Test
-#        run: cd build ; ctest -j 10 --output-on-failure
-
-# macos-12 is deprecated (https://github.com/actions/runner-images/issues/10721)
-#  macos-12:
-#    runs-on: macos-12 # https://github.com/actions/runner-images/blob/main/images/macos/macos-12-Readme.md
-#    strategy:
-#      matrix:
-#        xcode: ['13.1', '13.2.1', '13.3.1', '13.4.1', '14.0', '14.0.1', '14.1']
-#    env:
-#      DEVELOPER_DIR: /Applications/Xcode_${{ matrix.xcode }}.app/Contents/Developer
-#
-#    steps:
-#      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-#      - name: Run CMake
-#        run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DJSON_FastTests=ON
-#      - name: Build
-#        run: cmake --build build --parallel 10
-#      - name: Test
-#        run: cd build ; ctest -j 10 --output-on-failure
-
-  macos-13:
-    runs-on: macos-13 # https://github.com/actions/runner-images/blob/main/images/macos/macos-13-Readme.md
-    strategy:
-      matrix:
-        xcode: ['14.1', '14.2', '14.3', '14.3.1', '15.0.1', '15.1', '15.2']
-    env:
-      DEVELOPER_DIR: /Applications/Xcode_${{ matrix.xcode }}.app/Contents/Developer
-
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-      - name: Run CMake
-        run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DJSON_FastTests=ON
-      - name: Build
-        run: cmake --build build --parallel 10
-      - name: Test
-        run: cd build ; ctest -j 10 --output-on-failure
-
   macos-14:
     runs-on: macos-14 # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-Readme.md
     strategy:
       matrix:
-        xcode: ['15.3', '15.4']
+        xcode: ['15.0.1', '15.1', '15.2', '15.3', '15.4']
     env:
       DEVELOPER_DIR: /Applications/Xcode_${{ matrix.xcode }}.app/Contents/Developer
 
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Run CMake
         run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DJSON_FastTests=ON
       - name: Build
@@ -91,12 +40,14 @@ jobs:
     runs-on: macos-15 # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-Readme.md
     strategy:
       matrix:
-        xcode: ['16.0', '16.1', '16.2']
+        xcode: ['16.0', '16.1', '16.2', '16.3', '16.4', '26.0.1']
     env:
       DEVELOPER_DIR: /Applications/Xcode_${{ matrix.xcode }}.app/Contents/Developer
 
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Run CMake
         run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DJSON_FastTests=ON
       - name: Build
@@ -111,7 +62,9 @@ jobs:
         standard: [11, 14, 17, 20, 23, 26]
 
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Run CMake
         run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DJSON_TestStandards=${{ matrix.standard }}
       - name: Build

.github/workflows/publish_documentation.yml

@@ -27,11 +27,11 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
 
       - name: Install virtual environment
         run: make install_venv -C docs/mkdocs
@@ -40,7 +40,7 @@ jobs:
         run: make build -C docs/mkdocs
 
       - name: Deploy documentation
-        uses: peaceiris/actions-gh-pages@4f9cc6602d3f66b9c108549d475ec49e8ef4d45e # v4.0.0
+        uses: peaceiris/actions-gh-pages@84c30a85c19949d7eee79c4ff27748b70285e453 # v4.1.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./docs/mkdocs/site

.github/workflows/scorecards.yml

@@ -36,17 +36,17 @@ jobs:
 
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
       - name: "Checkout code"
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           persist-credentials: false
 
       - name: "Run analysis"
-        uses: ossf/scorecard-action@f49aabe0b5af0936a0987cfb85d86b75731b0186 # v2.4.1
+        uses: ossf/scorecard-action@4eaacf0543bb3f2c246792bd56e8cdeffafb205a # v2.4.3
         with:
           results_file: results.sarif
           results_format: sarif
@@ -68,7 +68,7 @@ jobs:
       # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
       # format to the repository Actions tab.
       - name: "Upload artifact"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: SARIF file
           path: results.sarif
@@ -76,6 +76,6 @@ jobs:
 
       # Upload the results to GitHub's code scanning dashboard.
       - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@fc7e4a0fa01c3cca5fd6a1fddec5c0740c977aa2 # v3.28.14
+        uses: github/codeql-action/upload-sarif@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4.36.2
         with:
           sarif_file: results.sarif

.github/workflows/semgrep.yml

@@ -0,0 +1,56 @@
+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+
+# This workflow file requires a free account on Semgrep.dev to
+# manage rules, file ignores, notifications, and more.
+#
+# See https://semgrep.dev/docs
+
+name: Semgrep
+
+on:
+  push:
+    branches: [ "develop" ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ "develop" ]
+  schedule:
+    - cron: '23 2 * * 4'
+
+permissions:
+  contents: read
+
+jobs:
+  semgrep:
+    permissions:
+      contents: read # for actions/checkout to fetch code
+      security-events: write # for github/codeql-action/upload-sarif to upload SARIF results
+      actions: read # only required for a private repository by github/codeql-action/upload-sarif to get the Action run status
+    name: Scan
+    runs-on: ubuntu-latest
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
+        with:
+          egress-policy: audit
+
+      # Checkout project source
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+
+      # Scan code using project's configuration on https://semgrep.dev/manage
+      - uses: returntocorp/semgrep-action@713efdd345f3035192eaa63f56867b88e63e4e5d
+        with:
+          publishToken: ${{ secrets.SEMGREP_APP_TOKEN }}
+          publishDeployment: ${{ secrets.SEMGREP_DEPLOYMENT_ID }}
+          generateSarif: "1"
+
+      # Upload SARIF file generated in previous step
+      - name: Upload SARIF file
+        uses: github/codeql-action/upload-sarif@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4.36.2
+        with:
+          sarif_file: semgrep.sarif
+        if: always()

.github/workflows/stale.yml

@@ -16,11 +16,11 @@ jobs:
 
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
-      - uses: actions/stale@5bef64f19d7facfb25b37b414482c7164d639639 # v9.1.0
+      - uses: actions/stale@eb5cf3af3ac0a1aa4c9c45633dd1ae542a27a899 # v10.3.0
         with:
           stale-issue-label: 'state: stale'
           stale-pr-label: 'state: stale'

.github/workflows/ubuntu.yml

@@ -21,9 +21,11 @@ jobs:
     runs-on: ubuntu-latest
     container: gcc:latest
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
@@ -33,7 +35,9 @@ jobs:
     runs-on: ubuntu-latest
     container: ghcr.io/nlohmann/json-ci:v2.4.0
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
@@ -46,15 +50,17 @@ jobs:
         target: [ci_test_amalgamation, ci_test_single_header, ci_cppcheck, ci_cpplint, ci_reproducible_tests, ci_non_git_tests, ci_offline_testdata, ci_reuse_compliance, ci_test_valgrind]
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
       - name: Install Valgrind
         run: sudo apt-get update ; sudo apt-get install -y valgrind
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
@@ -69,9 +75,11 @@ jobs:
     steps:
       - name: Install git, clang-tools, iwyu (ci_single_binaries), and unzip
         run: apt-get update ; apt-get install -y git clang-tools iwyu unzip
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
@@ -86,9 +94,11 @@ jobs:
     steps:
       - name: Install build-essential
         run: apt-get update ; apt-get install -y build-essential unzip wget git libssl-dev
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
@@ -98,11 +108,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Install dependencies and de_DE locale
         run: |
           sudo apt-get clean
@@ -115,15 +127,16 @@ jobs:
       - name: Build
         run: cmake --build build --target ci_test_coverage
       - name: Archive coverage report
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: code-coverage-report
           path: ${{ github.workspace }}/build/html
       - name: Publish report to Coveralls
-        uses: coverallsapp/github-action@648a8eb78e6d50909eff900e4ec85cab4524a45b # v2.3.6
+        uses: coverallsapp/github-action@5cbfd81b66ca5d10c19b062c04de0199c215fb6e # v2.3.7
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           path-to-lcov: ${{ github.workspace }}/build/json.info.filtered.noexcept
+          fail-on-error: false
 
   ci_test_compilers_gcc_old:
     runs-on: ubuntu-latest
@@ -132,7 +145,9 @@ jobs:
         compiler: ['4.8', '4.9', '5', '6']
     container: ghcr.io/nlohmann/json-ci:v2.4.0
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Run CMake
         run: CXX=g++-${{ matrix.compiler }} cmake -S . -B build -DJSON_CI=On
       - name: Build
@@ -143,12 +158,14 @@ jobs:
     strategy:
       matrix:
         # older GCC docker images (4, 5, 6) fail to check out code
-        compiler: ['7', '8', '9', '10', '11', '12', '13', '14', 'latest']
+        compiler: ['7', '8', '9', '10', '11', '12', '13', '14', '15', 'latest']
     container: gcc:${{ matrix.compiler }}
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
@@ -161,11 +178,11 @@ jobs:
         compiler: ['3.4', '3.5', '3.6', '3.7', '3.8', '3.9', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14', '15-bullseye', '16', '17', '18', '19', '20', 'latest']
     container: silkeh/clang:${{ matrix.compiler }}
     steps:
-      - name: Install unzip and git
-        run: apt-get update ; apt-get install -y unzip git
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
       - name: Set env FORCE_STDCPPFS_FLAG for clang 7 / 8 / 9 / 10
         run: echo "JSON_FORCED_GLOBAL_COMPILE_OPTIONS=-DJSON_HAS_FILESYSTEM=0;-DJSON_HAS_EXPERIMENTAL_FILESYSTEM=0" >> "$GITHUB_ENV"
         if: ${{ matrix.compiler == '7' || matrix.compiler == '8' || matrix.compiler == '9' || matrix.compiler == '10' }}
@@ -181,9 +198,11 @@ jobs:
       matrix:
         standard: [11, 14, 17, 20, 23, 26]
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
@@ -199,9 +218,11 @@ jobs:
     steps:
       - name: Install git and unzip
         run: apt-get update ; apt-get install -y git unzip
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build with libc++
@@ -215,17 +236,51 @@ jobs:
     runs-on: ubuntu-latest
     container: ghcr.io/nlohmann/json-ci:v2.4.0
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
         run: cmake --build build --target ci_cuda_example
 
+  ci_module_cpp20:
+    strategy:
+      matrix:
+        container: ['gcc:latest', 'silkeh/clang:latest']
+    runs-on: ubuntu-latest
+    container: ${{ matrix.container }}
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+      # The module test uses `import std;`, which needs CMake's experimental
+      # import-std support. Its opt-in token is CMake-version-specific, so pin
+      # CMake to the version whose token is set in tests/module_cpp20/CMakeLists.txt.
+      - name: Get pinned CMake and ninja
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
+        with:
+          cmakeVersion: 4.3.4
+      # Clang: the std library module is provided by libc++ (the image's libstdc++
+      # ships none), and the image's libc++ module manifest has a broken relative
+      # path — repoint it at the real module sources.
+      - name: Use libc++ and fix its module manifest path (Clang)
+        if: matrix.container == 'silkeh/clang:latest'
+        run: |
+          echo "CXXFLAGS=-stdlib=libc++" >> "$GITHUB_ENV"
+          mkdir -p /usr/lib/share && ln -sf /usr/lib/llvm-*/share/libc++ /usr/lib/share/libc++
+      - name: Run CMake
+        run: cmake -S . -B build -DJSON_CI=On
+      - name: Build
+        run: cmake --build build --target ci_module_cpp20
+
   ci_icpc:
     runs-on: ubuntu-latest
     container: ghcr.io/nlohmann/json-ci:v2.2.0
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
@@ -233,6 +288,26 @@ jobs:
           . /opt/intel/oneapi/setvars.sh
           cmake --build build --target ci_icpc
 
+  ci_emscripten:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
+        with:
+          egress-policy: audit
+
+      - name: Install emscripten
+        uses: mymindstorm/setup-emsdk@4528d102f7230f0e7b276855c01ea1159be0e984 # v16
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+      - name: Get latest CMake and ninja
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
+      - name: Run CMake
+        run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=$EMSDK/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake -GNinja
+      - name: Build
+        run: cmake --build build
+
   ci_test_documentation:
     runs-on: ubuntu-latest
     strategy:
@@ -240,11 +315,13 @@ jobs:
         target: [ci_test_examples, ci_test_build_documentation]
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
         with:
           egress-policy: audit
 
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build

.github/workflows/windows.yml

@@ -18,15 +18,17 @@ concurrency:
 
 jobs:
   mingw:
-    runs-on: windows-2019
+    runs-on: windows-2022
     strategy:
       matrix:
         architecture: [x64, x86]
 
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Set up MinGW
-        uses: egor-tensin/setup-mingw@84c781b557efd538dec66bde06988d81cd3138cf # v2.2.0
+        uses: egor-tensin/setup-mingw@41b837e47d7f85214629d255b9c4bc3fcbe9fd63 # v3.0
         with:
           platform: ${{ matrix.architecture }}
           version: 12.2.0 # https://github.com/egor-tensin/setup-mingw/issues/14
@@ -37,98 +39,103 @@ jobs:
       - name: Test
         run: cd build ; ctest -j 10 -C Debug --output-on-failure
 
-  msvc2019:
-    runs-on: windows-2019
+  msvc:
     strategy:
       matrix:
         build_type: [Debug, Release]
         architecture: [Win32, x64]
+        std_version: [default, latest]
 
-    steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Run CMake
-      run: cmake -S . -B build -G "Visual Studio 16 2019" -A ${{ matrix.architecture }} -DJSON_BuildTests=On -DCMAKE_CXX_FLAGS="/W4 /WX"
-      if: matrix.build_type == 'Release'
-    - name: Run CMake
-      run: cmake -S . -B build -G "Visual Studio 16 2019" -A ${{ matrix.architecture }} -DJSON_BuildTests=On -DJSON_FastTests=ON -DCMAKE_CXX_FLAGS="/W4 /WX"
-      if: matrix.build_type == 'Debug'
-    - name: Build
-      run: cmake --build build --config ${{ matrix.build_type }} --parallel 10
-    - name: Test
-      run: cd build ; ctest -j 10 -C ${{ matrix.build_type }} --output-on-failure
-
-  msvc2019_latest:
-    runs-on: windows-2019
-
-    steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Run CMake
-      run: cmake -S . -B build -G "Visual Studio 16 2019" -DJSON_BuildTests=On -DCMAKE_CXX_FLAGS="/permissive- /std:c++latest /utf-8 /W4 /WX"
-    - name: Build
-      run: cmake --build build --config Release --parallel 10
-    - name: Test
-      run: cd build ; ctest -j 10 -C Release --output-on-failure
-
-  msvc2022:
-    runs-on: windows-2022
-    strategy:
-      matrix:
-        build_type: [Debug, Release]
-        architecture: [Win32, x64]
-
-    steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Run CMake
-      run: cmake -S . -B build -G "Visual Studio 17 2022" -A ${{ matrix.architecture }} -DJSON_BuildTests=On -DCMAKE_CXX_FLAGS="/W4 /WX"
-      if: matrix.build_type == 'Release'
-    - name: Run CMake
-      run: cmake -S . -B build -G "Visual Studio 17 2022" -A ${{ matrix.architecture }} -DJSON_BuildTests=On -DJSON_FastTests=ON -DCMAKE_CXX_FLAGS="/W4 /WX"
-      if: matrix.build_type == 'Debug'
-    - name: Build
-      run: cmake --build build --config ${{ matrix.build_type }} --parallel 10
-    - name: Test
-      run: cd build ; ctest -j 10 -C ${{ matrix.build_type }} --output-on-failure
-
-  msvc2022_latest:
     runs-on: windows-2022
 
     steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Run CMake
-      run: cmake -S . -B build -G "Visual Studio 17 2022" -DJSON_BuildTests=On -DCMAKE_CXX_FLAGS="/permissive- /std:c++latest /utf-8 /W4 /WX"
-    - name: Build
-      run: cmake --build build --config Release --parallel 10
-    - name: Test
-      run: cd build ; ctest -j 10 -C Release --output-on-failure
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+      - name: Set extra CXX_FLAGS for latest std_version
+        id: cxxflags
+        run: |
+          if [ "${{ matrix.std_version }}" = "latest" ]; then
+            echo "flags=/permissive- /std:c++latest /utf-8 /W4 /WX" >> $GITHUB_ENV
+          else
+            echo "flags=/W4 /WX" >> $GITHUB_ENV
+          fi
+        shell: bash
+      - name: Run CMake (Release)
+        run: cmake -S . -B build -G "Visual Studio 17 2022" -A ${{ matrix.architecture }} -DJSON_BuildTests=On -DCMAKE_CXX_FLAGS="$env:flags"
+        if: matrix.build_type == 'Release'
+        shell: pwsh
+      - name: Run CMake (Debug)
+        run: cmake -S . -B build -G "Visual Studio 17 2022" -A ${{ matrix.architecture }} -DJSON_BuildTests=On -DJSON_FastTests=ON -DCMAKE_CXX_FLAGS="$env:flags"
+        if: matrix.build_type == 'Debug'
+        shell: pwsh
+      - name: Build
+        run: cmake --build build --config ${{ matrix.build_type }} --parallel 10
+      - name: Test
+        run: cd build ; ctest -j 10 -C ${{ matrix.build_type }} --output-on-failure
 
   clang:
-    runs-on: windows-2019
+    runs-on: windows-2022
     strategy:
       matrix:
-        version: [11, 12, 13, 14, 15]
+        version: [11.0.1, 12.0.1, 13.0.1, 14.0.6, 15.0.7, 16.0.6, 18.1.8, 19.1.7, 20.1.8]
 
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Install Clang
-        run: curl -fsSL -o LLVM${{ matrix.version }}.exe https://github.com/llvm/llvm-project/releases/download/llvmorg-${{ matrix.version }}.0.0/LLVM-${{ matrix.version }}.0.0-win64.exe ; 7z x LLVM${{ matrix.version }}.exe -y -o"C:/Program Files/LLVM"
+        run: curl -fsSL -o LLVM${{ matrix.version }}.exe https://github.com/llvm/llvm-project/releases/download/llvmorg-${{ matrix.version }}/LLVM-${{ matrix.version }}-win64.exe ; 7z x LLVM${{ matrix.version }}.exe -y -o"C:/Program Files/LLVM"
+      - name: Set up MinGW
+        uses: egor-tensin/setup-mingw@41b837e47d7f85214629d255b9c4bc3fcbe9fd63 # v3.0
+        with:
+          platform: x64
+          version: 12.2.0 # https://github.com/egor-tensin/setup-mingw/issues/14
       - name: Run CMake
-        run: cmake -S . -B build -DCMAKE_CXX_COMPILER="C:/Program Files/LLVM/bin/clang++.exe" -G"MinGW Makefiles" -DCMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On
+        run: cmake -S . -B build ^
+             -DCMAKE_CXX_COMPILER="C:/Program Files/LLVM/bin/clang++.exe" ^
+             -DCMAKE_CXX_FLAGS="--target=x86_64-w64-mingw32 -stdlib=libstdc++ -pthread" ^
+             -DCMAKE_EXE_LINKER_FLAGS="-lwinpthread" ^
+             -G"MinGW Makefiles" ^
+             -DCMAKE_BUILD_TYPE=Debug ^
+             -DJSON_BuildTests=On
       - name: Build
         run: cmake --build build --parallel 10
       - name: Test
         run: cd build ; ctest -j 10 -C Debug --exclude-regex "test-unicode" --output-on-failure
 
-  clang-cl-11:
-    runs-on: windows-2019
+  clang-cl-12:
+    runs-on: windows-2022
     strategy:
       matrix:
         architecture: [Win32, x64]
 
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
       - name: Run CMake
-        run: cmake -S . -B build -G "Visual Studio 16 2019" -A ${{ matrix.architecture }} -T ClangCL -DJSON_BuildTests=On
+        run: cmake -S . -B build -G "Visual Studio 17 2022" -A ${{ matrix.architecture }} -T ClangCL -DJSON_BuildTests=On
       - name: Build
         run: cmake --build build --config Debug --parallel 10
       - name: Test
         run: cd build ; ctest -j 10 -C Debug --exclude-regex "test-unicode" --output-on-failure
+
+  ci_module_cpp20:
+    runs-on: windows-2022
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+      # The module test uses `import std;`, which needs CMake's experimental
+      # import-std support. Its opt-in token is CMake-version-specific, so pin
+      # CMake to the version whose token is set in tests/module_cpp20/CMakeLists.txt.
+      - name: Get pinned CMake and ninja
+        uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
+        with:
+          cmakeVersion: 4.3.4
+      - name: Run CMake (Debug)
+        run: cmake -S . -B build -G "Visual Studio 17 2022" -DJSON_CI=ON -DCMAKE_CXX_FLAGS="/permissive- /std:c++latest /utf-8 /W4 /WX"
+      - name: Build
+        run: cmake --build build --config Debug --target ci_module_cpp20
+        

.reuse/dep5

@@ -4,7 +4,7 @@ Upstream-Contact: Niels Lohmann <mail@nlohmann.me>
 Source: https://github.com/nlohmann/json
 
 Files: *
-Copyright: 2013-2025 Niels Lohmann <https://nlohmann.me>
+Copyright: 2013-2026 Niels Lohmann <https://nlohmann.me>
 License: MIT
 
 Files: include/nlohmann/thirdparty/hedley.hpp

CMakeLists.txt

@@ -20,18 +20,29 @@ endif()
 ##
 ##
 set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
-include(ExternalProject)
-
-##
-## OPTIONS
-##
 
 if (POLICY CMP0077)
     # Allow CMake 3.13+ to override options when using FetchContent / add_subdirectory.
     cmake_policy(SET CMP0077 NEW)
 endif ()
 
-# VERSION_GREATER_EQUAL is not available in CMake 3.1
+# ---- C++ Modules Support (optional) ----
+option(NLOHMANN_JSON_BUILD_MODULES "Build C++ modules support" OFF)
+
+if(NLOHMANN_JSON_BUILD_MODULES)
+    if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.28)
+        message(STATUS "Building nlohmann.json C++ module")
+        add_subdirectory(src/modules)
+    else()
+        message(WARNING "Skipping nlohmann.json C++ module (requires CMake 3.28+, found ${CMAKE_VERSION})")
+    endif()
+endif()
+
+##
+## OPTIONS
+##
+
+# VERSION_GREATER_EQUAL is not available in older CMake (< 3.7)
 if(${MAIN_PROJECT} AND (${CMAKE_VERSION} VERSION_EQUAL 3.13 OR ${CMAKE_VERSION} VERSION_GREATER 3.13))
     set(JSON_BuildTests_INIT ON)
 else()
@@ -86,7 +97,7 @@ if (NOT JSON_ImplicitConversions)
 endif()
 
 if (JSON_DisableEnumSerialization)
-    message(STATUS "Enum integer serialization is disabled (JSON_DISABLE_ENUM_SERIALIZATION=0)")
+    message(STATUS "Enum integer serialization is disabled (JSON_DISABLE_ENUM_SERIALIZATION=1)")
 endif()
 
 if (JSON_LegacyDiscardedValueComparison)
@@ -152,7 +163,7 @@ if (MSVC)
 endif()
 
 # Install a pkg-config file, so other tools can find this.
-CONFIGURE_FILE(
+configure_file(
     "${CMAKE_CURRENT_SOURCE_DIR}/cmake/pkg-config.pc.in"
     "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}.pc"
     @ONLY
@@ -162,9 +173,11 @@ CONFIGURE_FILE(
 ## TESTS
 ## create and configure the unit test target
 ##
-if (JSON_BuildTests)
+# Only build tests when JSON_BuildTests is set and testing has not been
+# disabled by a parent project via BUILD_TESTING (see the CTest module, which
+# also calls enable_testing()).
+if (JSON_BuildTests AND (NOT DEFINED BUILD_TESTING OR BUILD_TESTING))
     include(CTest)
-    enable_testing()
     add_subdirectory(tests)
 endif()
 
@@ -200,7 +213,7 @@ if(JSON_Install)
         install(
             FILES ${NLOHMANN_NATVIS_FILE}
             DESTINATION .
-    )
+        )
     endif()
     export(
         TARGETS ${NLOHMANN_JSON_TARGET_NAME}

FILES.md

@@ -9,6 +9,30 @@ This file describes the source for supporting files; that is, files that are not
 
 ## Continuous Integration
 
+### `.github/workflows`
+
+The [GitHub Actions](https://docs.github.com/en/actions) workflows that build, test, and analyze the library. Each file in this folder defines one workflow:
+
+- `ubuntu.yml`, `macos.yml`, `windows.yml` — build and run the test suite on Linux, macOS, and Windows.
+- `check_amalgamation.yml` — verify that the single-header amalgamation in `single_include` is up to date on pull requests.
+- `comment_check_amalgamation.yml` — comment on a pull request when the amalgamation check failed.
+- `cifuzz.yml` — run short fuzzing sessions via [OSS-Fuzz CIFuzz](https://google.github.io/oss-fuzz/getting-started/continuous-integration/) on pull requests.
+- `codeql-analysis.yml` — run [CodeQL](https://codeql.github.com) code scanning.
+- `flawfinder.yml` — run the [Flawfinder](https://dwheeler.com/flawfinder/) static analysis.
+- `semgrep.yml` — run [Semgrep](https://semgrep.dev) static analysis.
+- `scorecards.yml` — run the [OpenSSF Scorecard](https://securityscorecards.dev) supply-chain security checks.
+- `dependency-review.yml` — scan dependency changes in pull requests for known vulnerabilities.
+- `labeler.yml` — the "Pull Request Labeler" workflow (see `.github/labeler.yml`).
+- `stale.yml` — comment on and close stale issues and pull requests.
+- `publish_documentation.yml` — build and publish the documentation on every merge to the `develop` branch.
+
+Further documentation:
+
+- [Workflow syntax for GitHub Actions](https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions)
+
+> [!IMPORTANT]
+> The folder `.github/workflows` is predetermined by GitHub.
+
 ### `.cirrus.yml`
 
 Configuration file for the pipeline at [Cirrus CI](https://cirrus-ci.com/github/nlohmann/json).
@@ -92,7 +116,7 @@ Further documentation:
 
 ### `.github/dependabot.yml`
 
-The configuration of [dependabot](https://github.com/dependabot) which ensures the dependencies (GitHub actions and Python packages used in the CI) remain up-to-date.
+The configuration of [dependabot](https://github.com/dependabot) which ensures the dependencies (GitHub actions and Python packages used in the CI) remain up to date.
 
 Further documentation:
 
@@ -123,7 +147,7 @@ Further documentation:
 > [!IMPORTANT]
 > The folder `.github/ISSUE_TEMPLATE` is predetermined by GitHub.
 
-### `.github/ISSUE_TEMPLATE/config.yaml`
+### `.github/ISSUE_TEMPLATE/config.yml`
 
 Issue template chooser configuration. The file is used to configure the dialog when a new issue is created.
 
@@ -132,7 +156,7 @@ Further documentation:
 - [Configuring issue templates for your repository](https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/configuring-issue-templates-for-your-repository)
 
 > [!IMPORTANT]
-> The filename `.github/ISSUE_TEMPLATE/config.yaml` is predetermined by GitHub.
+> The filename `.github/ISSUE_TEMPLATE/config.yml` is predetermined by GitHub.
 
 ### `.github/labeler.yml`
 
@@ -165,7 +189,7 @@ Further documentation:
 - [Adding a security policy to your repository](https://docs.github.com/en/code-security/getting-started/adding-a-security-policy-to-your-repository)
 
 > [!IMPORTANT]
-> The filename `.github/SECURITY.yml` is predetermined by GitHub.
+> The filename `.github/SECURITY.md` is predetermined by GitHub.
 
 > [!NOTE]
 > The file is part of the documentation and is included in `docs/mkdocs/docs/community/security_policy.md`.
@@ -185,7 +209,7 @@ Further documentation:
 
 ### `.reuse/dep5`
 
-The file defines the licenses of certain third-party component in the repository. The root `Makefile` contains a target `reuse` that checks for compliance.
+The file defines the licenses of certain third-party components in the repository. The root `Makefile` contains a target `reuse` that checks for compliance.
 
 Further documentation:
 
@@ -212,7 +236,7 @@ Further information:
 
 ### `LICENSES`
 
-A folder that contains every license of all licenses files (library and third-party code).
+A folder that contains every license of all license files (library and third-party code).
 
 Further documentation:
 
@@ -234,6 +258,16 @@ make BUILD.bazel
 
 ### `meson.build`
 
+The build definition for the [Meson](https://mesonbuild.com) build system.
+
 ### `Package.swift`
 
-### `WORKSPACE.bazel`
+The package manifest for the [Swift Package Manager](https://www.swift.org/package-manager/).
+
+### `MODULE.bazel`
+
+The module definition for [Bazel](https://bazel.build)'s [Bzlmod](https://bazel.build/external/module) dependency system. It complements `BUILD.bazel` and replaces the previously used `WORKSPACE.bazel`.
+
+Further documentation:
+
+- [Bazel modules](https://bazel.build/external/module)

LICENSE.MIT

@@ -1,6 +1,6 @@
 MIT License 
 
-Copyright (c) 2013-2025 Niels Lohmann
+Copyright (c) 2013-2026 Niels Lohmann
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

LICENSES/CC0-1.0.txt

@@ -0,0 +1,121 @@
+Creative Commons Legal Code
+
+CC0 1.0 Universal
+
+    CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE
+    LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN
+    ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS
+    INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES
+    REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS
+    PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM
+    THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED
+    HEREUNDER.
+
+Statement of Purpose
+
+The laws of most jurisdictions throughout the world automatically confer
+exclusive Copyright and Related Rights (defined below) upon the creator
+and subsequent owner(s) (each and all, an "owner") of an original work of
+authorship and/or a database (each, a "Work").
+
+Certain owners wish to permanently relinquish those rights to a Work for
+the purpose of contributing to a commons of creative, cultural and
+scientific works ("Commons") that the public can reliably and without fear
+of later claims of infringement build upon, modify, incorporate in other
+works, reuse and redistribute as freely as possible in any form whatsoever
+and for any purposes, including without limitation commercial purposes.
+These owners may contribute to the Commons to promote the ideal of a free
+culture and the further production of creative, cultural and scientific
+works, or to gain reputation or greater distribution for their Work in
+part through the use and efforts of others.
+
+For these and/or other purposes and motivations, and without any
+expectation of additional consideration or compensation, the person
+associating CC0 with a Work (the "Affirmer"), to the extent that he or she
+is an owner of Copyright and Related Rights in the Work, voluntarily
+elects to apply CC0 to the Work and publicly distribute the Work under its
+terms, with knowledge of his or her Copyright and Related Rights in the
+Work and the meaning and intended legal effect of CC0 on those rights.
+
+1. Copyright and Related Rights. A Work made available under CC0 may be
+protected by copyright and related or neighboring rights ("Copyright and
+Related Rights"). Copyright and Related Rights include, but are not
+limited to, the following:
+
+  i. the right to reproduce, adapt, distribute, perform, display,
+     communicate, and translate a Work;
+ ii. moral rights retained by the original author(s) and/or performer(s);
+iii. publicity and privacy rights pertaining to a person's image or
+     likeness depicted in a Work;
+ iv. rights protecting against unfair competition in regards to a Work,
+     subject to the limitations in paragraph 4(a), below;
+  v. rights protecting the extraction, dissemination, use and reuse of data
+     in a Work;
+ vi. database rights (such as those arising under Directive 96/9/EC of the
+     European Parliament and of the Council of 11 March 1996 on the legal
+     protection of databases, and under any national implementation
+     thereof, including any amended or successor version of such
+     directive); and
+vii. other similar, equivalent or corresponding rights throughout the
+     world based on applicable law or treaty, and any national
+     implementations thereof.
+
+2. Waiver. To the greatest extent permitted by, but not in contravention
+of, applicable law, Affirmer hereby overtly, fully, permanently,
+irrevocably and unconditionally waives, abandons, and surrenders all of
+Affirmer's Copyright and Related Rights and associated claims and causes
+of action, whether now known or unknown (including existing as well as
+future claims and causes of action), in the Work (i) in all territories
+worldwide, (ii) for the maximum duration provided by applicable law or
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+medium and for any number of copies, and (iv) for any purpose whatsoever,
+including without limitation commercial, advertising or promotional
+purposes (the "Waiver"). Affirmer makes the Waiver for the benefit of each
+member of the public at large and to the detriment of Affirmer's heirs and
+successors, fully intending that such Waiver shall not be subject to
+revocation, rescission, cancellation, termination, or any other legal or
+equitable action to disrupt the quiet enjoyment of the Work by the public
+as contemplated by Affirmer's express Statement of Purpose.
+
+3. Public License Fallback. Should any part of the Waiver for any reason
+be judged legally invalid or ineffective under applicable law, then the
+Waiver shall be preserved to the maximum extent permitted taking into
+account Affirmer's express Statement of Purpose. In addition, to the
+extent the Waiver is so judged Affirmer hereby grants to each affected
+person a royalty-free, non transferable, non sublicensable, non exclusive,
+irrevocable and unconditional license to exercise Affirmer's Copyright and
+Related Rights in the Work (i) in all territories worldwide, (ii) for the
+maximum duration provided by applicable law or treaty (including future
+time extensions), (iii) in any current or future medium and for any number
+of copies, and (iv) for any purpose whatsoever, including without
+limitation commercial, advertising or promotional purposes (the
+"License"). The License shall be deemed effective as of the date CC0 was
+applied by Affirmer to the Work. Should any part of the License for any
+reason be judged legally invalid or ineffective under applicable law, such
+partial invalidity or ineffectiveness shall not invalidate the remainder
+of the License, and in such case Affirmer hereby affirms that he or she
+will not (i) exercise any of his or her remaining Copyright and Related
+Rights in the Work or (ii) assert any associated claims and causes of
+action with respect to the Work, in either case contrary to Affirmer's
+express Statement of Purpose.
+
+4. Limitations and Disclaimers.
+
+ a. No trademark or patent rights held by Affirmer are waived, abandoned,
+    surrendered, licensed or otherwise affected by this document.
+ b. Affirmer offers the Work as-is and makes no representations or
+    warranties of any kind concerning the Work, express, implied,
+    statutory or otherwise, including without limitation warranties of
+    title, merchantability, fitness for a particular purpose, non
+    infringement, or the absence of latent or other defects, accuracy, or
+    the present or absence of errors, whether or not discoverable, all to
+    the greatest extent permissible under applicable law.
+ c. Affirmer disclaims responsibility for clearing rights of other persons
+    that may apply to the Work or any use thereof, including without
+    limitation any person's Copyright and Related Rights in the Work.
+    Further, Affirmer disclaims responsibility for obtaining any necessary
+    consents, permissions or other rights required for any use of the
+    Work.
+ d. Affirmer understands and acknowledges that Creative Commons is not a
+    party to this document and has no duty or obligation with respect to
+    this CC0 or use of the Work.

Makefile

@@ -205,7 +205,7 @@ json.tar.xz:
 # We use `-X` to make the resulting ZIP file reproducible, see
 # <https://content.pivotal.io/blog/barriers-to-deterministic-reproducible-zip-files>.
 include.zip: BUILD.bazel
-	zip -9 --recurse-paths -X include.zip $(SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) BUILD.bazel WORKSPACE.bazel meson.build LICENSE.MIT
+	zip -9 --recurse-paths -X include.zip $(SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) BUILD.bazel MODULE.bazel meson.build LICENSE.MIT
 
 # Create the files for a release and add signatures and hashes.
 release: include.zip json.tar.xz
@@ -258,8 +258,8 @@ serve_header:
 ##########################################################################
 
 reuse:
-	pipx run reuse annotate --recursive single_include include -tjson --license MIT --copyright "Niels Lohmann <https://nlohmann.me>" --year "2013-2025" --merge-copyrights
-	pipx run reuse annotate $(TESTS_SRCS) -tjson_support --license MIT --copyright "Niels Lohmann <https://nlohmann.me>" --year "2013-2025" --merge-copyrights
+	pipx run reuse annotate --recursive single_include include -tjson --license MIT --copyright "Niels Lohmann <https://nlohmann.me>" --year "2013-2026" --merge-copyrights
+	pipx run reuse annotate $(TESTS_SRCS) -tjson_support --license MIT --copyright "Niels Lohmann <https://nlohmann.me>" --year "2013-2026" --merge-copyrights
 	pipx run reuse lint
 
 spdx:

README.md

@@ -11,7 +11,7 @@
 [![Fuzzing Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/json.svg)](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:json)
 [![Try online](https://img.shields.io/badge/try-online-blue.svg)](https://wandbox.org/permlink/1mp10JbaANo6FUc7)
 [![Documentation](https://img.shields.io/badge/docs-mkdocs-blue.svg)](https://json.nlohmann.me)
-[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
+[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/develop/LICENSE.MIT)
 [![GitHub Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
 [![Packaging status](https://repology.org/badge/tiny-repos/nlohmann-json.svg)](https://repology.org/project/nlohmann-json/versions)
 [![GitHub Downloads](https://img.shields.io/github/downloads/nlohmann/json/total)](https://github.com/nlohmann/json/releases)
@@ -19,6 +19,7 @@
 [![Average time to resolve an issue](https://isitmaintained.com/badge/resolution/nlohmann/json.svg)](https://isitmaintained.com/project/nlohmann/json "Average time to resolve an issue")
 [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/289/badge)](https://bestpractices.coreinfrastructure.org/projects/289)
 [![OpenSSF Scorecard](https://api.scorecard.dev/projects/github.com/nlohmann/json/badge)](https://scorecard.dev/viewer/?uri=github.com/nlohmann/json)
+[![Backup Status](https://app.cloudback.it/badge/nlohmann/json)](https://cloudback.it)
 [![GitHub Sponsors](https://img.shields.io/badge/GitHub-Sponsors-ff69b4)](https://github.com/sponsors/nlohmann)
 [![REUSE status](https://api.reuse.software/badge/github.com/nlohmann/json)](https://api.reuse.software/info/github.com/nlohmann/json)
 [![Discord](https://img.shields.io/discord/1003743314341793913)](https://discord.gg/6mrGXKvX7y)
@@ -30,7 +31,7 @@
 - [Examples](#examples)
   - [Read JSON from a file](#read-json-from-a-file)
   - [Creating `json` objects from JSON literals](#creating-json-objects-from-json-literals)
-  - [JSON as first-class data type](#json-as-first-class-data-type)
+  - [JSON as a first-class data type](#json-as-a-first-class-data-type)
   - [Serialization / Deserialization](#serialization--deserialization)
   - [STL-like access](#stl-like-access)
   - [Conversion from STL containers](#conversion-from-stl-containers)
@@ -57,7 +58,7 @@
 
 There are myriads of [JSON](https://json.org) libraries out there, and each may even have its reason to exist. Our class had these design goals:
 
-- **Intuitive syntax**. In languages such as Python, JSON feels like a first class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you'll know what I mean.
+- **Intuitive syntax**. In languages such as Python, JSON feels like a first-class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you'll know what I mean.
 
 - **Trivial integration**. Our whole code consists of a single header file [`json.hpp`](https://github.com/nlohmann/json/blob/develop/single_include/nlohmann/json.hpp). That's it. No library, no subproject, no dependencies, no complex build system. The class is written in vanilla C++11. All in all, everything should require no adjustment of your compiler flags or project settings. The library is also included in all popular [package managers](https://json.nlohmann.me/integration/package_managers/).
 
@@ -69,7 +70,7 @@ Other aspects were not so important to us:
 
 - **Speed**. There are certainly [faster JSON libraries](https://github.com/miloyip/nativejson-benchmark#parsing-time) out there. However, if your goal is to speed up your development by adding JSON support with a single header, then this library is the way to go. If you know how to use a `std::vector` or `std::map`, you are already set.
 
-See the [contribution guidelines](https://github.com/nlohmann/json/blob/master/.github/CONTRIBUTING.md#please-dont) for more information.
+See the [contribution guidelines](https://github.com/nlohmann/json/blob/develop/.github/CONTRIBUTING.md#please-dont) for more information.
 
 ## Sponsors
 
@@ -79,6 +80,8 @@ You can sponsor this library at [GitHub Sponsors](https://github.com/sponsors/nl
 
 - [Martti Laine](https://github.com/codeclown)
 - [Paul Harrington](https://github.com/phrrngtn)
+- [Mercedes-Benz Group](https://github.com/mercedes-benz)
+- [Ryan McCaffery](https://github.com/mccaffers)
 
 ### :label: Named Sponsors
 
@@ -107,7 +110,7 @@ Thanks everyone!
 
 :bug: If you found a **bug**, please check the [**FAQ**](https://json.nlohmann.me/home/faq/) if it is a known issue or the result of a design decision. Please also have a look at the [**issue list**](https://github.com/nlohmann/json/issues) before you [**create a new issue**](https://github.com/nlohmann/json/issues/new/choose). Please provide as much information as possible to help us understand and reproduce your issue.
 
-There is also a [**docset**](https://github.com/Kapeli/Dash-User-Contributions/tree/master/docsets/JSON_for_Modern_C%2B%2B) for the documentation browsers [Dash](https://kapeli.com/dash), [Velocity](https://velocity.silverlakesoftware.com), and [Zeal](https://zealdocs.org) that contains the full [documentation](https://json.nlohmann.me) as offline resource.
+There is also a [**docset**](https://github.com/Kapeli/Dash-User-Contributions/tree/master/docsets/JSON_for_Modern_C%2B%2B) for the documentation browsers [Dash](https://kapeli.com/dash), [Velocity](https://velocity.silverlakesoftware.com), and [Zeal](https://zealdocs.org) that contains the full [documentation](https://json.nlohmann.me) as an offline resource.
 
 ## Quick reference
 
@@ -136,7 +139,7 @@ There is also a [**docset**](https://github.com/Kapeli/Dash-User-Contributions/t
 
 Here are some examples to give you an idea how to use the class.
 
-Beside the examples below, you may want to:
+Besides the examples below, you may want to:
 
 → Check the [documentation](https://json.nlohmann.me/)\
 → Browse the [standalone example files](https://github.com/nlohmann/json/tree/develop/docs/mkdocs/docs/examples)\
@@ -157,9 +160,22 @@ std::ifstream f("example.json");
 json data = json::parse(f);
 ```
 
+If using modules (enabled with `NLOHMANN_JSON_BUILD_MODULES`), this example becomes:
+```cpp
+import std;
+import nlohmann.json;
+
+using json = nlohmann::json;
+
+// ...
+
+std::ifstream f("example.json");
+json data = json::parse(f);
+```
+
 ### Creating `json` objects from JSON literals
 
-Assume you want to create hard-code this literal JSON value in a file, as a `json` object:
+Assume you want to hard-code this literal JSON value as a `json` object:
 
 ```json
 {
@@ -195,7 +211,7 @@ json ex3 = {
 };
 ```
 
-### JSON as first-class data type
+### JSON as a first-class data type
 
 Here are some examples to give you an idea how to use the class.
 
@@ -224,13 +240,13 @@ With this library, you could write:
 // create an empty structure (null)
 json j;
 
-// add a number that is stored as double (note the implicit conversion of j to an object)
+// add a number stored as double (note the implicit conversion of j to an object)
 j["pi"] = 3.141;
 
-// add a Boolean that is stored as bool
+// add a Boolean stored as bool
 j["happy"] = true;
 
-// add a string that is stored as std::string
+// add a string stored as std::string
 j["name"] = "Niels";
 
 // add another null object by passing nullptr
@@ -239,7 +255,7 @@ j["nothing"] = nullptr;
 // add an object inside the object
 j["answer"]["everything"] = 42;
 
-// add an array that is stored as std::vector (using an initializer list)
+// add an array stored as std::vector (using an initializer list)
 j["list"] = { 1, 0, 2 };
 
 // add another object (using an initializer list of pairs)
@@ -331,7 +347,7 @@ Note the difference between serialization and assignment:
 json j_string = "this is a string";
 
 // retrieve the string value
-auto cpp_string = j_string.template get<std::string>();
+auto cpp_string = j_string.get<std::string>();
 // retrieve the string value (alternative when a variable already exists)
 std::string cpp_string2;
 j_string.get_to(cpp_string2);
@@ -340,7 +356,7 @@ j_string.get_to(cpp_string2);
 std::string serialized_string = j_string.dump();
 
 // output of original string
-std::cout << cpp_string << " == " << cpp_string2 << " == " << j_string.template get<std::string>() << '\n';
+std::cout << cpp_string << " == " << cpp_string2 << " == " << j_string.get<std::string>() << '\n';
 // output of serialized value
 std::cout << j_string << " == " << serialized_string << std::endl;
 ```
@@ -349,7 +365,7 @@ std::cout << j_string << " == " << serialized_string << std::endl;
 
 Note the library only supports UTF-8. When you store strings with different encodings in the library, calling [`dump()`](https://json.nlohmann.me/api/basic_json/dump/) may throw an exception unless `json::error_handler_t::replace` or `json::error_handler_t::ignore` are used as error handlers.
 
-#### To/from streams (e.g. files, string streams)
+#### To/from streams (e.g., files, string streams)
 
 You can also use streams to serialize and deserialize:
 
@@ -382,7 +398,7 @@ Please note that setting the exception bit for `failbit` is inappropriate for th
 
 #### Read from iterator range
 
-You can also parse JSON from an iterator range; that is, from any container accessible by iterators whose `value_type` is an integral type of 1, 2 or 4 bytes, which will be interpreted as UTF-8, UTF-16 and UTF-32 respectively. For instance, a `std::vector<std::uint8_t>`, or a `std::list<std::uint16_t>`:
+You can also parse JSON from an iterator range; that is, from any container accessible by iterators whose `value_type` is an integral type of 1, 2, or 4 bytes, which will be interpreted as UTF-8, UTF-16, and UTF-32 respectively. For instance, a `std::vector<std::uint8_t>`, or a `std::list<std::uint16_t>`:
 
 ```cpp
 std::vector<std::uint8_t> v = {'t', 'r', 'u', 'e'};
@@ -413,6 +429,8 @@ struct MyIterator {
     using reference = const char&;
     using iterator_category = std::input_iterator_tag;
 
+    explicit MyIterator(MyContainer* tgt = nullptr) : target(tgt) {}
+
     MyIterator& operator++() {
         target->advance();
         return *this;
@@ -434,12 +452,12 @@ MyIterator begin(MyContainer& tgt) {
 }
 
 MyIterator end(const MyContainer&) {
-    return {};
+    return MyIterator{};
 }
 
 void foo() {
     MyContainer c;
-    json j = json::parse(c);
+    json j = json::parse(begin(c), end(c));
 }
 ```
 
@@ -486,7 +504,7 @@ To implement your own SAX handler, proceed as follows:
 2. Create an object of your SAX interface class, e.g. `my_sax`.
 3. Call `bool json::sax_parse(input, &my_sax)`; where the first parameter can be any input like a string or an input stream and the second parameter is a pointer to your SAX interface.
 
-Note the `sax_parse` function only returns a `bool` indicating the result of the last executed SAX event. It does not return a  `json` value - it is up to you to decide what to do with the SAX events. Furthermore, no exceptions are thrown in case of a parse error - it is up to you what to do with the exception object passed to your `parse_error` implementation. Internally, the SAX interface is used for the DOM parser (class `json_sax_dom_parser`) as well as the acceptor (`json_sax_acceptor`), see file [`json_sax.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/json_sax.hpp).
+Note the `sax_parse` function only returns a `bool` indicating the result of the last executed SAX event. It does not return a  `json` value - it is up to you to decide what to do with the SAX events. Furthermore, no exceptions are thrown in case of a parse error -- it is up to you what to do with the exception object passed to your `parse_error` implementation. Internally, the SAX interface is used for the DOM parser (class `json_sax_dom_parser`) as well as the acceptor (`json_sax_acceptor`), see file [`json_sax.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/json_sax.hpp).
 
 ### STL-like access
 
@@ -513,7 +531,7 @@ for (auto& element : j) {
 }
 
 // getter/setter
-const auto tmp = j[0].template get<std::string>();
+const auto tmp = j[0].get<std::string>();
 j[1] = 42;
 bool foo = j.at(2);
 
@@ -618,7 +636,7 @@ json j_umset(c_umset); // both entries for "one" are used
 // maybe ["one", "two", "one", "four"]
 ```
 
-Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys can construct an `std::string` and whose values can be used to construct JSON values (see examples above) can be used to create a JSON object. Note that in case of multimaps only one key is used in the JSON object and the value depends on the internal order of the STL container.
+Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys can construct an `std::string` and whose values can be used to construct JSON values (see examples above) can be used to create a JSON object. Note that in case of multimaps, only one key is used in the JSON object and the value depends on the internal order of the STL container.
 
 ```cpp
 std::map<std::string, int> c_map { {"one", 1}, {"two", 2}, {"three", 3} };
@@ -640,7 +658,7 @@ json j_ummap(c_ummap); // only one entry for key "three" is used
 
 ### JSON Pointer and JSON Patch
 
-The library supports **JSON Pointer** ([RFC 6901](https://tools.ietf.org/html/rfc6901)) as alternative means to address structured values. On top of this, **JSON Patch** ([RFC 6902](https://tools.ietf.org/html/rfc6902)) allows describing differences between two JSON values - effectively allowing patch and diff operations known from Unix.
+The library supports **JSON Pointer** ([RFC 6901](https://tools.ietf.org/html/rfc6901)) as an alternative means to address structured values. On top of this, **JSON Patch** ([RFC 6902](https://tools.ietf.org/html/rfc6902)) allows describing differences between two JSON values -- effectively allowing patch and diff operations known from Unix.
 
 ```cpp
 // a JSON value
@@ -720,7 +738,7 @@ You can switch off implicit conversions by defining `JSON_USE_IMPLICIT_CONVERSIO
 // strings
 std::string s1 = "Hello, world!";
 json js = s1;
-auto s2 = js.template get<std::string>();
+auto s2 = js.get<std::string>();
 // NOT RECOMMENDED
 std::string s3 = js;
 std::string s4;
@@ -729,7 +747,7 @@ s4 = js;
 // Booleans
 bool b1 = true;
 json jb = b1;
-auto b2 = jb.template get<bool>();
+auto b2 = jb.get<bool>();
 // NOT RECOMMENDED
 bool b3 = jb;
 bool b4;
@@ -738,11 +756,11 @@ b4 = jb;
 // numbers
 int i = 42;
 json jn = i;
-auto f = jn.template get<double>();
+auto f = jn.get<double>();
 // NOT RECOMMENDED
-double f2 = jb;
+double f2 = jn;
 double f3;
-f3 = jb;
+f3 = jn;
 
 // etc.
 ```
@@ -781,9 +799,9 @@ j["age"] = p.age;
 
 // convert from JSON: copy each value from the JSON object
 ns::person p {
-    j["name"].template get<std::string>(),
-    j["address"].template get<std::string>(),
-    j["age"].template get<int>()
+    j["name"].get<std::string>(),
+    j["address"].get<std::string>(),
+    j["age"].get<int>()
 };
 ```
 
@@ -800,7 +818,7 @@ std::cout << j << std::endl;
 // {"address":"744 Evergreen Terrace","age":60,"name":"Ned Flanders"}
 
 // conversion: json -> person
-auto p2 = j.template get<ns::person>();
+auto p2 = j.get<ns::person>();
 
 // that's it
 assert(p == p2);
@@ -827,21 +845,21 @@ namespace ns {
 ```
 
 That's all! When calling the `json` constructor with your type, your custom `to_json` method will be automatically called.
-Likewise, when calling `template get<your_type>()` or `get_to(your_type&)`, the `from_json` method will be called.
+Likewise, when calling `get<your_type>()` or `get_to(your_type&)`, the `from_json` method will be called.
 
 Some important things:
 
 - Those methods **MUST** be in your type's namespace (which can be the global namespace), or the library will not be able to locate them (in this example, they are in namespace `ns`, where `person` is defined).
 - Those methods **MUST** be available (e.g., proper headers must be included) everywhere you use these conversions. Look at [issue 1108](https://github.com/nlohmann/json/issues/1108) for errors that may occur otherwise.
-- When using `template get<your_type>()`, `your_type` **MUST** be [DefaultConstructible](https://en.cppreference.com/w/cpp/named_req/DefaultConstructible). (There is a way to bypass this requirement described later.)
+- When using `get<your_type>()`, `your_type` **MUST** be [DefaultConstructible](https://en.cppreference.com/w/cpp/named_req/DefaultConstructible). (There is a way to bypass this requirement described later.)
 - In function `from_json`, use function [`at()`](https://json.nlohmann.me/api/basic_json/at/) to access the object values rather than `operator[]`. In case a key does not exist, `at` throws an exception that you can handle, whereas `operator[]` exhibits undefined behavior.
 - You do not need to add serializers or deserializers for STL types like `std::vector`: the library already implements these.
 
 #### Simplify your life with macros
 
-If you just want to serialize/deserialize some structs, the `to_json`/`from_json` functions can be a lot of boilerplate. There are [**several macros**](https://json.nlohmann.me/features/arbitrary_types/#simplify-your-life-with-macros) to make your life easier as long as you (1) want to use a JSON object as serialization and (2) want to use the member variable names as object keys in that object.
+If you just want to serialize/deserialize some structs, the `to_json`/`from_json` functions can be a lot of boilerplate. There are [**several macros**](https://json.nlohmann.me/api/macros/#serializationdeserialization-macros) to make your life easier as long as you want to use a JSON object as serialization.
 
-Which macro to choose depends on whether private member variables need to be accessed, a deserialization is needed, missing values should yield an error or should be replaced by default values, and if derived classes are used. See [this overview to choose the right one for your use case](https://json.nlohmann.me/api/macros/#serializationdeserialization-macros).
+Which macro to choose depends on whether private member variables need to be accessed, a deserialization is needed, missing values should yield an error or should be replaced by default values, and if derived classes are used. See [this overview to choose the right one for your use case](https://json.nlohmann.me/features/arbitrary_types/#simplify-your-life-with-macros).
 
 ##### Example usage of macros
 
@@ -853,6 +871,18 @@ namespace ns {
 }
 ```
 
+If you want to inherit the `person` struct and add a field to it, it can be done with:
+
+```cpp
+namespace ns {
+    struct person_derived : person {
+        std::string email;
+    };
+    
+    NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE(person_derived, person, email)
+}
+```
+
 Here is another example with private members, where [`NLOHMANN_DEFINE_TYPE_INTRUSIVE`](https://json.nlohmann.me/api/macros/nlohmann_define_type_intrusive/) is needed:
 
 ```cpp
@@ -869,11 +899,29 @@ namespace ns {
 }
 ```
 
+Or in case if you use some naming convention that you do not want to expose to JSON:
+
+```cpp
+namespace ns {
+    class address {
+      private:
+        std::string m_street;
+        int m_housenumber;
+        int m_postcode;
+
+      public:
+        NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_NAMES(address, "street", m_street,
+                                                           "housenumber", m_housenumber,
+                                                           "postcode", m_postcode)
+    };
+}
+```
+
 #### How do I convert third-party types?
 
 This requires a bit more advanced technique. But first, let's see how this conversion mechanism works:
 
-The library uses **JSON Serializers** to convert types to json.
+The library uses **JSON Serializers** to convert types to JSON.
 The default serializer for `nlohmann::json` is `nlohmann::adl_serializer` (ADL means [Argument-Dependent Lookup](https://en.cppreference.com/w/cpp/language/adl)).
 
 It is implemented like this (simplified):
@@ -913,8 +961,8 @@ namespace nlohmann {
             if (j.is_null()) {
                 opt = boost::none;
             } else {
-                opt = j.template get<T>(); // same as above, but with
-                                           // adl_serializer<T>::from_json
+                opt = j.get<T>(); // same as above, but with
+                                  // adl_serializer<T>::from_json
             }
         }
     };
@@ -923,7 +971,7 @@ namespace nlohmann {
 
 #### How can I use `get()` for non-default constructible/non-copyable types?
 
-There is a way, if your type is [MoveConstructible](https://en.cppreference.com/w/cpp/named_req/MoveConstructible). You will need to specialize the `adl_serializer` as well, but with a special `from_json` overload:
+There is a way if your type is [MoveConstructible](https://en.cppreference.com/w/cpp/named_req/MoveConstructible). You will need to specialize the `adl_serializer` as well, but with a special `from_json` overload:
 
 ```cpp
 struct move_only_type {
@@ -941,7 +989,7 @@ namespace nlohmann {
         // note: the return type is no longer 'void', and the method only takes
         // one argument
         static move_only_type from_json(const json& j) {
-            return {j.template get<int>()};
+            return {j.get<int>()};
         }
 
         // Here's the catch! You must provide a to_json method! Otherwise, you
@@ -1005,14 +1053,14 @@ struct bad_serializer
     static void to_json(const BasicJsonType& j, T& value) {
       // this calls BasicJsonType::json_serializer<T>::from_json(j, value)
       // if BasicJsonType::json_serializer == bad_serializer ... oops!
-      value = j.template get<T>(); // oops!
+      value = j.get<T>(); // oops!
     }
 };
 ```
 
 ### Specializing enum conversion
 
-By default, enum values are serialized to JSON as integers. In some cases this could result in undesired behavior. If an enum is modified or re-ordered after data has been serialized to JSON, the later de-serialized JSON data may be undefined or a different enum value than was originally intended.
+By default, enum values are serialized to JSON as integers. In some cases, this could result in undesired behavior. If an enum is modified or re-ordered after data has been serialized to JSON, the later deserialized JSON data may be undefined or a different enum value than was originally intended.
 
 It is possible to more precisely specify how a given enum is mapped to and from JSON as shown below:
 
@@ -1045,11 +1093,11 @@ assert(j == "stopped");
 
 // json string to enum
 json j3 = "running";
-assert(j3.template get<TaskState>() == TS_RUNNING);
+assert(j3.get<TaskState>() == TS_RUNNING);
 
 // undefined json value to enum (where the first map entry above is the default)
 json jPi = 3.14;
-assert(jPi.template get<TaskState>() == TS_INVALID);
+assert(jPi.get<TaskState>() == TS_INVALID);
 ```
 
 Just as in [Arbitrary Type Conversions](#arbitrary-types-conversions) above,
@@ -1059,7 +1107,7 @@ Just as in [Arbitrary Type Conversions](#arbitrary-types-conversions) above,
 
 Other Important points:
 
-- When using `template get<ENUM_TYPE>()`, undefined JSON values will default to the first pair specified in your map. Select this default pair carefully.
+- When using `get<ENUM_TYPE>()`, undefined JSON values will default to the first pair specified in your map. Select this default pair carefully. If you desire an exception in this circumstance use `NLOHMANN_JSON_SERIALIZE_ENUM_STRICT()` which behaves identically except for throwing an exception on unrecognized values.
 - If an enum or JSON value is specified more than once in your map, the first matching occurrence from the top of the map will be returned when converting to or from JSON.
 
 ### Binary formats (BSON, CBOR, MessagePack, UBJSON, and BJData)
@@ -1141,7 +1189,7 @@ The library is used in multiple projects, applications, operating systems, etc.
 
 ## Supported compilers
 
-Though it's 2025 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
+Though it's 2026 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
 
 - GCC 4.8 - 14.2 (and possibly later)
 - Clang 3.4 - 21.0 (and possibly later)
@@ -1168,7 +1216,7 @@ Please note:
 
     The code compiles successfully with [Android NDK](https://developer.android.com/ndk/index.html?hl=ml), Revision 9 - 11 (and possibly later) and [CrystaX's Android NDK](https://www.crystax.net/en/android/ndk) version 10.
 
-- For GCC running on MinGW or Android SDK, the error `'to_string' is not a member of 'std'` (or similarly, for `strtod` or `strtof`) may occur. Note this is not an issue with the code,  but rather with the compiler itself. On Android, see above to build with a newer environment.  For MinGW, please refer to [this site](https://tehsausage.com/mingw-to-string) and [this discussion](https://github.com/nlohmann/json/issues/136) for information on how to fix this bug. For Android NDK using `APP_STL := gnustl_static`, please refer to [this discussion](https://github.com/nlohmann/json/issues/219).
+- For GCC running on MinGW or Android SDK, the error `'to_string' is not a member of 'std'` (or similarly, for `strtod` or `strtof`) may occur. Note this is not an issue with the code, but rather with the compiler itself. On Android, see above to build with a newer environment.  For MinGW, please refer to [this site](https://tehsausage.com/mingw-to-string) and [this discussion](https://github.com/nlohmann/json/issues/136) for information on how to fix this bug. For Android NDK using `APP_STL := gnustl_static`, please refer to [this discussion](https://github.com/nlohmann/json/issues/219).
 
 - Unsupported versions of GCC and Clang are rejected by `#error` directives. This can be switched off by defining `JSON_SKIP_UNSUPPORTED_COMPILER_CHECK`. Note that you can expect no support in this case.
 
@@ -1187,7 +1235,7 @@ using json = nlohmann::json;
 
 to the files you want to process JSON and set the necessary switches to enable C++11 (e.g., `-std=c++11` for GCC and Clang).
 
-You can further use file [`include/nlohmann/json_fwd.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/json_fwd.hpp) for forward-declarations. The installation of json_fwd.hpp (as part of cmake's install step), can be achieved by setting `-DJSON_MultipleHeaders=ON`.
+You can further use file [`include/nlohmann/json_fwd.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/json_fwd.hpp) for forward-declarations. The installation of `json_fwd.hpp` (as part of cmake's install step) can be achieved by setting `-DJSON_MultipleHeaders=ON`.
 
 ### CMake
 
@@ -1249,7 +1297,7 @@ FetchContent_MakeAvailable(json)
 target_link_libraries(foo PRIVATE nlohmann_json::nlohmann_json)
 ```
 
-**Note**: It is recommended to use the URL approach described above which is supported as of version 3.10.0. See
+**Note**: It is recommended to use the URL approach described above, which is supported as of version 3.10.0. See
 <https://json.nlohmann.me/integration/cmake/#fetchcontent> for more information.
 
 #### Supporting Both
@@ -1320,7 +1368,7 @@ pkg-config nlohmann_json --cflags
 
 The class is licensed under the [MIT License](https://opensource.org/licenses/MIT):
 
-Copyright &copy; 2013-2025 [Niels Lohmann](https://nlohmann.me)
+Copyright &copy; 2013-2026 [Niels Lohmann](https://nlohmann.me)
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
@@ -1371,13 +1419,13 @@ I deeply appreciate the help of the following people.
 9. [Florian Weber](https://github.com/Florianjw) fixed a bug in and improved the performance of the comparison operators.
 10. [Eric Cornelius](https://github.com/EricMCornelius) pointed out a bug in the handling with NaN and infinity values. He also improved the performance of the string escaping.
 11. [易思龙](https://github.com/likebeta) implemented a conversion from anonymous enums.
-12. [kepkin](https://github.com/kepkin) patiently pushed forward the support for Microsoft Visual studio.
+12. [kepkin](https://github.com/kepkin) patiently pushed forward the support for Microsoft Visual Studio.
 13. [gregmarr](https://github.com/gregmarr) simplified the implementation of reverse iterators and helped with numerous hints and improvements. In particular, he pushed forward the implementation of user-defined types.
 14. [Caio Luppi](https://github.com/caiovlp) fixed a bug in the Unicode handling.
 15. [dariomt](https://github.com/dariomt) fixed some typos in the examples.
 16. [Daniel Frey](https://github.com/d-frey) cleaned up some pointers and implemented exception-safe memory allocation.
 17. [Colin Hirsch](https://github.com/ColinH) took care of a small namespace issue.
-18. [Huu Nguyen](https://github.com/whoshuu) correct a variable name in the documentation.
+18. [Huu Nguyen](https://github.com/whoshuu) corrected a variable name in the documentation.
 19. [Silverweed](https://github.com/silverweed) overloaded `parse()` to accept an rvalue reference.
 20. [dariomt](https://github.com/dariomt) fixed a subtlety in MSVC type support and implemented the `get_ref()` function to get a reference to stored values.
 21. [ZahlGraf](https://github.com/ZahlGraf) added a workaround that allows compilation using Android NDK.
@@ -1412,14 +1460,14 @@ I deeply appreciate the help of the following people.
 50. [Jared Grubb](https://github.com/jaredgrubb) silenced a nasty documentation warning.
 51. [Yixin Zhang](https://github.com/qwename) fixed an integer overflow check.
 52. [Bosswestfalen](https://github.com/Bosswestfalen) merged two iterator classes into a smaller one.
-53. [Daniel599](https://github.com/Daniel599) helped to get Travis execute the tests with Clang's sanitizers.
+53. [Daniel599](https://github.com/Daniel599) helped to get Travis to execute the tests with Clang's sanitizers.
 54. [Jonathan Lee](https://github.com/vjon) fixed an example in the README file.
 55. [gnzlbg](https://github.com/gnzlbg) supported the implementation of user-defined types.
 56. [Alexej Harm](https://github.com/qis) helped to get the user-defined types working with Visual Studio.
 57. [Jared Grubb](https://github.com/jaredgrubb) supported the implementation of user-defined types.
 58. [EnricoBilla](https://github.com/EnricoBilla) noted a typo in an example.
 59. [Martin Hořeňovský](https://github.com/horenmar) found a way for a 2x speedup for the compilation time of the test suite.
-60. [ukhegg](https://github.com/ukhegg) found proposed an improvement for the examples section.
+60. [ukhegg](https://github.com/ukhegg) proposed an improvement for the examples section.
 61. [rswanson-ihi](https://github.com/rswanson-ihi) noted a typo in the README.
 62. [Mihai Stan](https://github.com/stanmihai4) fixed a bug in the comparison with `nullptr`s.
 63. [Tushar Maheshwari](https://github.com/tusharpm) added [cotire](https://github.com/sakra/cotire) support to speed up the compilation.
@@ -1433,7 +1481,7 @@ I deeply appreciate the help of the following people.
 71. [Vincent Thiery](https://github.com/vthiery) maintains a package for the Conan package manager.
 72. [Steffen](https://github.com/koemeet) fixed a potential issue with MSVC and `std::min`.
 73. [Mike Tzou](https://github.com/Chocobo1) fixed some typos.
-74. [amrcode](https://github.com/amrcode) noted a misleading documentation about comparison of floats.
+74. [amrcode](https://github.com/amrcode) noted misleading documentation about comparison of floats.
 75. [Oleg Endo](https://github.com/olegendo) reduced the memory consumption by replacing `<iostream>` with `<iosfwd>`.
 76. [dan-42](https://github.com/dan-42) cleaned up the CMake files to simplify including/reusing of the library.
 77. [Nikita Ofitserov](https://github.com/himikof) allowed for moving values from initializer lists.
@@ -1460,13 +1508,13 @@ I deeply appreciate the help of the following people.
 98. [Vadim Evard](https://github.com/Pipeliner) fixed a Markdown issue in the README.
 99. [zerodefect](https://github.com/zerodefect) fixed a compiler warning.
 100. [Kert](https://github.com/kaidokert) allowed to template the string type in the serialization and added the possibility to override the exceptional behavior.
-101. [mark-99](https://github.com/mark-99) helped fixing an ICC error.
+101. [mark-99](https://github.com/mark-99) helped fix an ICC error.
 102. [Patrik Huber](https://github.com/patrikhuber) fixed links in the README file.
 103. [johnfb](https://github.com/johnfb) found a bug in the implementation of CBOR's indefinite length strings.
 104. [Paul Fultz II](https://github.com/pfultz2) added a note on the cget package manager.
 105. [Wilson Lin](https://github.com/wla80) made the integration section of the README more concise.
 106. [RalfBielig](https://github.com/ralfbielig) detected and fixed a memory leak in the parser callback.
-107. [agrianius](https://github.com/agrianius) allowed to dump JSON to an alternative string type.
+107. [agrianius](https://github.com/agrianius) allowed dumping JSON to an alternative string type.
 108. [Kevin Tonon](https://github.com/ktonon) overworked the C++11 compiler checks in CMake.
 109. [Axel Huebl](https://github.com/ax3l) simplified a CMake check and added support for the [Spack package manager](https://spack.io).
 110. [Carlos O'Ryan](https://github.com/coryan) fixed a typo.
@@ -1515,12 +1563,12 @@ I deeply appreciate the help of the following people.
 153. [Ivor Wanders](https://github.com/iwanders) helped to reduce the CMake requirement to version 3.1.
 154. [njlr](https://github.com/njlr) updated the Buckaroo instructions.
 155. [Lion](https://github.com/lieff) fixed a compilation issue with GCC 7 on CentOS.
-156. [Isaac Nickaein](https://github.com/nickaein) improved the integer serialization performance and  implemented the `contains()` function.
+156. [Isaac Nickaein](https://github.com/nickaein) improved the integer serialization performance and implemented the `contains()` function.
 157. [past-due](https://github.com/past-due) suppressed an unfixable warning.
 158. [Elvis Oric](https://github.com/elvisoric) improved Meson support.
 159. [Matěj Plch](https://github.com/Afforix) fixed an example in the README.
 160. [Mark Beckwith](https://github.com/wythe) fixed a typo.
-161. [scinart](https://github.com/scinart) fixed bug in the serializer.
+161. [scinart](https://github.com/scinart) fixed a bug in the serializer.
 162. [Patrick Boettcher](https://github.com/pboettch) implemented `push_back()` and `pop_back()` for JSON Pointers.
 163. [Bruno Oliveira](https://github.com/nicoddemus) added support for Conda.
 164. [Michele Caini](https://github.com/skypjack) fixed links in the README.
@@ -1562,7 +1610,7 @@ I deeply appreciate the help of the following people.
 200. [Alexander “weej” Jones](https://github.com/alex-weej) fixed an example in the README.
 201. [Antoine Cœur](https://github.com/Coeur) fixed some typos in the documentation.
 202. [jothepro](https://github.com/jothepro) updated links to the Hunter package.
-203. [Dave Lee](https://github.com/kastiglione) fixed link in the README.
+203. [Dave Lee](https://github.com/kastiglione) fixed a link in the README.
 204. [Joël Lamotte](https://github.com/Klaim) added instruction for using Build2's package manager.
 205. [Paul Jurczak](https://github.com/pauljurczak) fixed an example in the README.
 206. [Sonu Lohani](https://github.com/sonulohani) fixed a warning.
@@ -1605,7 +1653,7 @@ I deeply appreciate the help of the following people.
 243. [raduteo](https://github.com/raduteo) fixed a warning.
 244. [David Pfahler](https://github.com/theShmoo) added the possibility to compile the library without I/O support.
 245. [Morten Fyhn Amundsen](https://github.com/mortenfyhn) fixed a typo.
-246. [jpl-mac](https://github.com/jpl-mac) allowed to treat the library as a system header in CMake.
+246. [jpl-mac](https://github.com/jpl-mac) allowed treating the library as a system header in CMake.
 247. [Jason Dsouza](https://github.com/jasmcaus) fixed the indentation of the CMake file.
 248. [offa](https://github.com/offa) added a link to Conan Center to the documentation.
 249. [TotalCaesar659](https://github.com/TotalCaesar659) updated the links in the documentation to use HTTPS.
@@ -1647,7 +1695,7 @@ I deeply appreciate the help of the following people.
 285. [Wolf Vollprecht](https://github.com/wolfv) added the `patch_inplace` function.
 286. [Jake Zimmerman](https://github.com/jez) highlighted common usage patterns in the README file.
 287. [NN](https://github.com/NN---) added the Visual Studio output directory to `.gitignore`.
-288. [Romain Reignier](https://github.com/romainreignier) improved the performance the vector output adapter.
+288. [Romain Reignier](https://github.com/romainreignier) improved the performance of the vector output adapter.
 289. [Mike](https://github.com/Mike-Leo-Smith) fixed the `std::iterator_traits`.
 290. [Richard Hozák](https://github.com/zxey) added macro `JSON_NO_ENUM` to disable default enum conversions.
 291. [vakokako](https://github.com/vakokako) fixed tests when compiling with C++20.
@@ -1694,9 +1742,9 @@ I deeply appreciate the help of the following people.
 332. [taro](https://github.com/tarolling) fixed a typo in the `CODEOWNERS` file.
 333. [Ikko Eltociear Ashimine](https://github.com/eltociear) fixed a typo.
 334. [Felix Yan](https://github.com/felixonmars) fixed a typo in the README.
-335. [HO-COOH](https://github.com/HO-COOH) fixed a parentheses in the documentation.
+335. [HO-COOH](https://github.com/HO-COOH) fixed a parenthesis in the documentation.
 336. [Ivor Wanders](https://github.com/iwanders) fixed the examples to catch exception by `const&`.
-337. [miny1233](https://github.com/miny1233) fixed a parentheses in the documentation.
+337. [miny1233](https://github.com/miny1233) fixed a parenthesis in the documentation.
 338. [tomalakgeretkal](https://github.com/tomalakgeretkal) fixed a compilation error.
 339. [alferov](https://github.com/ALF-ONE) fixed a compilation error.
 340. [Craig Scott](https://github.com/craigscott-crascit) fixed a deprecation warning in CMake.
@@ -1779,7 +1827,7 @@ The library itself consists of a single header file licensed under the MIT licen
 
 The library supports **Unicode input** as follows:
 
-- Only **UTF-8** encoded input is supported which is the default encoding for JSON according to [RFC 8259](https://tools.ietf.org/html/rfc8259.html#section-8.1).
+- Only **UTF-8** encoded input is supported, which is the default encoding for JSON according to [RFC 8259](https://tools.ietf.org/html/rfc8259.html#section-8.1).
 - `std::u16string` and `std::u32string` can be parsed, assuming UTF-16 and UTF-32 encoding, respectively. These encodings are not supported when reading from files or other input containers.
 - Other encodings such as Latin-1 or ISO 8859-1 are **not** supported and will yield parse or serialization errors.
 - [Unicode noncharacters](https://www.unicode.org/faq/private_use.html#nonchar1) will not be replaced by the library.
@@ -1793,7 +1841,7 @@ The library supports **Unicode input** as follows:
 This library does not support comments by default. It does so for three reasons:
 
 1. Comments are not part of the [JSON specification](https://tools.ietf.org/html/rfc8259). You may argue that `//` or `/* */` are allowed in JavaScript, but JSON is not JavaScript.
-2. This was not an oversight: Douglas Crockford [wrote on this](https://plus.google.com/118095276221607585885/posts/RK8qyGVaGSr) in May 2012:
+2. This was not an oversight: Douglas Crockford [wrote on this](https://news.ycombinator.com/item?id=3912149) in May 2012:
   
     > I removed comments from JSON because I saw people were using them to hold parsing directives, a practice which would have destroyed interoperability.  I know that the lack of comments makes some people sad, but it shouldn't.
     >
@@ -1801,7 +1849,17 @@ This library does not support comments by default. It does so for three reasons:
   
 3. It is dangerous for interoperability if some libraries would add comment support while others don't. Please check [The Harmful Consequences of the Robustness Principle](https://tools.ietf.org/html/draft-iab-protocol-maintenance-01) on this.
 
-However, you can pass set parameter `ignore_comments` to true in the `parse` function to ignore `//` or `/* */` comments. Comments will then be treated as whitespace.
+However, you can set parameter `ignore_comments` to true in the `parse` function to ignore `//` or `/* */` comments. Comments will then be treated as whitespace.
+
+### Trailing commas
+
+The JSON specification does not allow trailing commas in arrays and objects, and hence this library is treating them as parsing errors by default.
+
+Like comments, you can set parameter `ignore_trailing_commas` to true in the `parse` function to ignore trailing commas in arrays and objects. Note that a single comma as the only content of the array or object (`[,]` or `{,}`) is not allowed, and multiple trailing commas (`[1,,]`) are not allowed either.
+
+This library does not add trailing commas when serializing JSON data.
+
+For more information, see [JSON With Commas and Comments (JWCC)](https://nigeltao.github.io/blog/2021/json-with-commas-comments.html).
 
 ### Order of object keys
 
@@ -1841,7 +1899,7 @@ ctest --output-on-failure
 
 Note that during the `ctest` stage, several JSON test files are downloaded from an [external repository](https://github.com/nlohmann/json_test_data). If policies forbid downloading artifacts during testing, you can download the files yourself and pass the directory with the test files via `-DJSON_TestDataDirectory=path` to CMake. Then, no Internet connectivity is required. See [issue #2189](https://github.com/nlohmann/json/issues/2189) for more information.
 
-If the test suite is not found, several test suites will fail like this:
+If the testdata is not found, several test suites will fail like this:
 
 ```
 ===============================================================================
@@ -1859,6 +1917,8 @@ json/tests/src/make_test_data_available.hpp:23: FATAL ERROR: REQUIRE( utils::che
 
 In case you have downloaded the library rather than checked out the code via Git, test `cmake_fetch_content_configure` will fail. Please execute `ctest -LE git_required` to skip these tests. See [issue #2189](https://github.com/nlohmann/json/issues/2189) for more information.
 
+Some tests are requiring network to be properly execute. They are labeled as `git_required`. Please execute `ctest -LE git_required` to skip these tests. See [issue #4851](https://github.com/nlohmann/json/issues/4851) for more information.
+
 Some tests change the installed files and hence make the whole process not reproducible. Please execute `ctest -LE not_reproducible` to skip these tests. See [issue #2324](https://github.com/nlohmann/json/issues/2324) for more information. Furthermore, assertions must be switched off to ensure reproducible builds (see [discussion 4494](https://github.com/nlohmann/json/discussions/4494)).
 
 Note you need to call `cmake -LE "not_reproducible|git_required"` to exclude both labels. See [issue #2596](https://github.com/nlohmann/json/issues/2596) for more information.

cmake/ci.cmake

@@ -212,6 +212,21 @@ add_custom_target(ci_test_legacycomparison
     COMMENT "Compile and test with legacy discarded value comparison enabled"
 )
 
+###############################################################################
+# Enable brace-init copy semantics.
+###############################################################################
+
+add_custom_target(ci_test_brace_init_copy_semantics
+    COMMAND ${CMAKE_COMMAND}
+    -DCMAKE_BUILD_TYPE=Debug -GNinja
+    -DJSON_BuildTests=ON -DJSON_FastTests=ON
+    -DCMAKE_CXX_FLAGS=-DJSON_BRACE_INIT_COPY_SEMANTICS=1
+    -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_brace_init_copy_semantics
+    COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_brace_init_copy_semantics
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_brace_init_copy_semantics && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
+    COMMENT "Compile and test with brace-init copy semantics enabled"
+)
+
 ###############################################################################
 # Disable global UDLs.
 ###############################################################################
@@ -659,6 +674,18 @@ add_custom_target(ci_cuda_example
     COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_cuda_example
 )
 
+###############################################################################
+# C++ 20 modules
+###############################################################################
+
+add_custom_target(ci_module_cpp20
+    COMMAND ${CMAKE_COMMAND}
+        -DCMAKE_BUILD_TYPE=Debug -GNinja 
+        -DJSON_CI=ON -DNLOHMANN_JSON_BUILD_MODULES=ON -DJSON_Install=ON
+        -S${PROJECT_SOURCE_DIR}/tests/module_cpp20 -B${PROJECT_BINARY_DIR}/ci_module_cpp20
+    COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/ci_module_cpp20
+)
+
 ###############################################################################
 # Intel C++ Compiler
 ###############################################################################

cmake/clang_flags.cmake

@@ -6,6 +6,7 @@
 # -Wno-padded                     We do not care about padding warnings.
 # -Wno-covered-switch-default     All switches list all cases and a default case.
 # -Wno-unsafe-buffer-usage        Otherwise Doctest would not compile.
+# -Wno-missing-noreturn           We found no way to silence this warning otherwise, see PR #4871
 
 set(CLANG_CXXFLAGS
     -Werror
@@ -17,4 +18,5 @@ set(CLANG_CXXFLAGS
     -Wno-padded
     -Wno-covered-switch-default
     -Wno-unsafe-buffer-usage
+    -Wno-missing-noreturn
 )

cmake/detect_libcpp_version.cpp

@@ -0,0 +1,31 @@
+/*
+ * Detect used C++ Standard Library
+ *
+ * This file is compiled and run via try_run in download_test_data.cmake.
+ */
+
+#include <cstdio>
+
+// see https://en.cppreference.com/w/cpp/header/ciso646
+#if __cplusplus >= 202002L
+    #include <version>
+#else
+    #include <ciso646>
+#endif
+
+int main()
+{
+#if defined(_LIBCPP_VERSION)
+    std::printf("LLVM C++ Standard Library (libc++), _LIBCPP_VERSION=%d", _LIBCPP_VERSION);
+#elif defined(__GLIBCXX__)
+    std::printf("GNU C++ Standard Library (libstdc++), __GLIBCXX__=%d", __GLIBCXX__);
+#elif defined(_MSVC_STL_VERSION)
+    std::printf("Microsoft C++ Standard Library (MSVC STL), _MSVC_STL_VERSION=%d", _MSVC_STL_VERSION);
+#elif defined(_LIBCUDACXX_VERSION)
+    std::printf("NVIDIA C++ Standard Library (libcudacxx), _LIBCUDACXX_VERSION=%d", _LIBCUDACXX_VERSION);
+#elif defined(EASTL_VERSION)
+    std::printf("Electronic Arts Standard Template Library (EASTL), EASTL_VERSION=%d", EASTL_VERSION);
+#else
+    std::printf("unknown");
+#endif
+}

cmake/download_test_data.cmake

@@ -1,32 +1,48 @@
 set(JSON_TEST_DATA_URL     https://github.com/nlohmann/json_test_data)
 set(JSON_TEST_DATA_VERSION 3.1.0)
 
+include(ExternalProject)
+
 # if variable is set, use test data from given directory rather than downloading them
 if(JSON_TestDataDirectory)
     message(STATUS "Using test data in ${JSON_TestDataDirectory}.")
     add_custom_target(download_test_data)
     file(WRITE ${CMAKE_BINARY_DIR}/include/test_data.hpp "#define TEST_DATA_DIRECTORY \"${JSON_TestDataDirectory}\"\n")
 else()
-    find_package(Git)
+    # create a header with the path to the downloaded test data
+    file(WRITE ${CMAKE_BINARY_DIR}/include/test_data.hpp "#define TEST_DATA_DIRECTORY \"${CMAKE_BINARY_DIR}/test_files\"\n")
+
+    # download test data from the GitHub tag source archive
+    ExternalProject_Add(download_test_data_project
+        URL "${JSON_TEST_DATA_URL}/archive/refs/tags/v${JSON_TEST_DATA_VERSION}.zip"
+        SOURCE_DIR "${CMAKE_BINARY_DIR}/test_files"
+        CONFIGURE_COMMAND ""
+        BUILD_COMMAND ""
+        INSTALL_COMMAND ""
+        LOG_DOWNLOAD TRUE
+        DOWNLOAD_EXTRACT_TIMESTAMP TRUE
+        EXCLUDE_FROM_ALL TRUE
+    )
+
     # target to download test data
     add_custom_target(download_test_data
-        COMMAND test -d json_test_data || ${GIT_EXECUTABLE} clone -c advice.detachedHead=false --branch v${JSON_TEST_DATA_VERSION} ${JSON_TEST_DATA_URL}.git --quiet --depth 1
-        COMMENT "Downloading test data from ${JSON_TEST_DATA_URL} (v${JSON_TEST_DATA_VERSION})"
-        WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
+        DEPENDS download_test_data_project
     )
-    # create a header with the path to the downloaded test data
-    file(WRITE ${CMAKE_BINARY_DIR}/include/test_data.hpp "#define TEST_DATA_DIRECTORY \"${CMAKE_BINARY_DIR}/json_test_data\"\n")
 endif()
 
 # determine the operating system (for debug and support purposes)
 find_program(UNAME_COMMAND uname)
-find_program(VER_COMMAND ver)
 find_program(LSB_RELEASE_COMMAND lsb_release)
 find_program(SW_VERS_COMMAND sw_vers)
 set(OS_VERSION_STRINGS "${CMAKE_SYSTEM}")
-if (VER_COMMAND)
-    execute_process(COMMAND ${VER_COMMAND} OUTPUT_VARIABLE VER_COMMAND_RESULT OUTPUT_STRIP_TRAILING_WHITESPACE)
-    set(OS_VERSION_STRINGS "${OS_VERSION_STRINGS}; ${VER_COMMAND_RESULT}")
+if (CMAKE_HOST_WIN32)
+    # "ver" is a cmd.exe builtin rather than a standalone executable, so it
+    # cannot be located with find_program and must be invoked through cmd
+    execute_process(COMMAND cmd /c ver OUTPUT_VARIABLE VER_COMMAND_RESULT ERROR_QUIET)
+    string(STRIP "${VER_COMMAND_RESULT}" VER_COMMAND_RESULT)
+    if (VER_COMMAND_RESULT)
+        set(OS_VERSION_STRINGS "${OS_VERSION_STRINGS}; ${VER_COMMAND_RESULT}")
+    endif()
 endif()
 if (SW_VERS_COMMAND)
     execute_process(COMMAND ${SW_VERS_COMMAND} OUTPUT_VARIABLE SW_VERS_COMMAND_RESULT OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_QUIET)
@@ -54,3 +70,22 @@ else()
 endif()
 string(REGEX REPLACE "[ ]*\n" "; " CXX_VERSION_RESULT "${CXX_VERSION_RESULT}")
 message(STATUS "Compiler: ${CXX_VERSION_RESULT}")
+
+# determine used C++ standard library (for debug and support purposes)
+if(CMAKE_CROSSCOMPILING)
+    set(LIBCPP_VERSION_OUTPUT_CACHED "could not be detected due to cross-compiling" CACHE STRING "Detected C++ standard library version")
+endif()
+if(NOT DEFINED LIBCPP_VERSION_OUTPUT_CACHED)
+    try_run(RUN_RESULT_VAR COMPILE_RESULT_VAR
+        "${CMAKE_BINARY_DIR}" SOURCES "${CMAKE_SOURCE_DIR}/cmake/detect_libcpp_version.cpp"
+        RUN_OUTPUT_VARIABLE LIBCPP_VERSION_OUTPUT
+        COMPILE_OUTPUT_VARIABLE LIBCPP_VERSION_COMPILE_OUTPUT
+    )
+    if(NOT LIBCPP_VERSION_OUTPUT)
+        set(LIBCPP_VERSION_OUTPUT "Unknown")
+        message(AUTHOR_WARNING "Failed to compile cmake/detect_libcpp_version to detect the used C++ standard library. This does not affect the library or the test cases. Please still create an issue at https://github.com/nlohmann/json to investigate this.\n${LIBCPP_VERSION_COMPILE_OUTPUT}")
+    endif()
+    set(LIBCPP_VERSION_OUTPUT_CACHED "${LIBCPP_VERSION_OUTPUT}" CACHE STRING "Detected C++ standard library version")
+endif()
+
+message(STATUS "C++ standard library: ${LIBCPP_VERSION_OUTPUT_CACHED}")

cmake/gcc_flags.cmake

@@ -1,13 +1,13 @@
-# Warning flags determined for GCC 14.2.0 with https://github.com/nlohmann/gcc_flags:
+# Warning flags determined for GCC 15.1.0 with https://github.com/nlohmann/gcc_flags:
 # Ignored GCC warnings:
-# -Wno-abi-tag                    We do not care about ABI tags.
-# -Wno-aggregate-return           The library uses aggregate returns.
-# -Wno-long-long                  The library uses the long long type to interface with system functions.
-# -Wno-namespaces                 The library uses namespaces.
-# -Wno-nrvo                       Doctest triggers this warning.
-# -Wno-padded                     We do not care about padding warnings.
-# -Wno-system-headers             We do not care about warnings in system headers.
-# -Wno-templates                  The library uses templates.
+# -Wno-abi-tag           We do not care about ABI tags.
+# -Wno-aggregate-return  The library uses aggregate returns.
+# -Wno-long-long         The library uses the long long type to interface with system functions.
+# -Wno-namespaces        The library uses namespaces.
+# -Wno-nrvo              Doctest triggers this warning.
+# -Wno-padded            We do not care about padding warnings.
+# -Wno-system-headers    We do not care about warnings in system headers.
+# -Wno-templates         The library uses templates.
 
 set(GCC_CXXFLAGS
     -pedantic
@@ -65,6 +65,7 @@ set(GCC_CXXFLAGS
     -Wanalyzer-tainted-offset
     -Wanalyzer-tainted-size
     -Wanalyzer-too-complex
+    -Wanalyzer-undefined-behavior-ptrdiff
     -Wanalyzer-undefined-behavior-strtok
     -Wanalyzer-unsafe-call-within-signal-handler
     -Wanalyzer-use-after-free
@@ -123,6 +124,7 @@ set(GCC_CXXFLAGS
     -Wcoverage-invalid-line-number
     -Wcoverage-mismatch
     -Wcoverage-too-many-conditions
+    -Wcoverage-too-many-paths
     -Wcpp
     -Wctad-maybe-unsupported
     -Wctor-dtor-privacy
@@ -130,6 +132,7 @@ set(GCC_CXXFLAGS
     -Wdangling-pointer=2
     -Wdangling-reference
     -Wdate-time
+    -Wdefaulted-function-deleted
     -Wdelete-incomplete
     -Wdelete-non-virtual-dtor
     -Wdeprecated
@@ -138,6 +141,8 @@ set(GCC_CXXFLAGS
     -Wdeprecated-declarations
     -Wdeprecated-enum-enum-conversion
     -Wdeprecated-enum-float-conversion
+    -Wdeprecated-literal-operator
+    -Wdeprecated-variadic-comma-omission
     -Wdisabled-optimization
     -Wdiv-by-zero
     -Wdouble-promotion
@@ -157,20 +162,21 @@ set(GCC_CXXFLAGS
     -Wfloat-conversion
     -Wfloat-equal
     -Wformat -Wformat-contains-nul
+    -Wformat -Wformat-diag
     -Wformat -Wformat-extra-args
     -Wformat -Wformat-nonliteral
+    -Wformat -Wformat-overflow=2
     -Wformat -Wformat-security
+    -Wformat -Wformat-signedness
+    -Wformat -Wformat-truncation=2
     -Wformat -Wformat-y2k
     -Wformat -Wformat-zero-length
-    -Wformat-diag
-    -Wformat-overflow=2
-    -Wformat-signedness
-    -Wformat-truncation=2
     -Wformat=2
     -Wframe-address
     -Wfree-nonheap-object
     -Wglobal-module
     -Whardened
+    -Wheader-guard
     -Whsa
     -Wif-not-aligned
     -Wignored-attributes
@@ -197,6 +203,7 @@ set(GCC_CXXFLAGS
     -Wno-long-long
     -Wlto-type-mismatch
     -Wmain
+    -Wmaybe-musttail-local-addr
     -Wmaybe-uninitialized
     -Wmemset-elt-size
     -Wmemset-transposed-args
@@ -215,6 +222,7 @@ set(GCC_CXXFLAGS
     -Wmultichar
     -Wmultiple-inheritance
     -Wmultistatement-macros
+    -Wmusttail-local-addr
     -Wno-namespaces
     -Wnarrowing
     -Wnoexcept
@@ -245,6 +253,7 @@ set(GCC_CXXFLAGS
     -Wpmf-conversions
     -Wpointer-arith
     -Wpointer-compare
+    -Wpragma-once-outside-header
     -Wpragmas
     -Wprio-ctor-dtor
     -Wpsabi
@@ -276,10 +285,12 @@ set(GCC_CXXFLAGS
     -Wsizeof-pointer-div
     -Wsizeof-pointer-memaccess
     -Wstack-protector
+    -Wstrict-aliasing
     -Wstrict-aliasing=3
     -Wstrict-null-sentinel
     -Wstrict-overflow
     -Wstring-compare
+    -Wstringop-overflow
     -Wstringop-overflow=4
     -Wstringop-overread
     -Wstringop-truncation
@@ -304,8 +315,12 @@ set(GCC_CXXFLAGS
     -Wsynth
     -Wno-system-headers
     -Wtautological-compare
+    -Wtemplate-body
+    -Wtemplate-id-cdtor
+    -Wtemplate-names-tu-local
     -Wno-templates
     -Wterminate
+    -Wtrailing-whitespace
     -Wtrampolines
     -Wtrigraphs
     -Wtrivial-auto-var-init

cmake/requirements/requirements-cppcheck.txt

@@ -1 +1 @@
-cppcheck==1.5.0
+cppcheck==1.5.1

cmake/requirements/requirements-cpplint.txt

@@ -1 +1 @@
-cpplint==2.0.1
+cpplint==2.0.2

cmake/requirements/requirements-reuse.txt

@@ -1 +1 @@
-reuse==5.0.2
+reuse==6.2.0

cmake/test.cmake

@@ -35,6 +35,8 @@ foreach(feature ${CMAKE_CXX_COMPILE_FEATURES})
         set(compiler_supports_cpp_20 TRUE)
     elseif (${feature} STREQUAL cxx_std_23)
         set(compiler_supports_cpp_23 TRUE)
+    elseif (${feature} STREQUAL cxx_std_26)
+        set(compiler_supports_cpp_26 TRUE)
     endif()
 endforeach()
 
@@ -92,7 +94,6 @@ function(json_test_set_test_options tests)
             target_compile_options(${test_interface} INTERFACE ${args_COMPILE_OPTIONS})
             target_link_libraries (${test_interface} INTERFACE ${args_LINK_LIBRARIES})
             target_link_options(${test_interface} INTERFACE ${args_LINK_OPTIONS})
-            #set_target_properties(${test_interface} PROPERTIES JSON_TEST_PROPERTIES "${args_TEST_PROPERTIES}")
             set_property(DIRECTORY PROPERTY
                 ${test_interface}_TEST_PROPERTIES "${args_TEST_PROPERTIES}"
             )
@@ -102,7 +103,6 @@ endfunction()
 
 # for internal use by _json_test_add_test()
 function(_json_test_apply_test_properties test_target properties_target)
-    #get_target_property(test_properties ${properties_target} JSON_TEST_PROPERTIES)
     get_property(test_properties DIRECTORY PROPERTY ${properties_target}_TEST_PROPERTIES)
     if(test_properties)
         set_tests_properties(${test_target} PROPERTIES ${test_properties})
@@ -213,10 +213,10 @@ function(json_test_add_test_for file)
 
     if("${args_NAME}" STREQUAL "")
         get_filename_component(file_basename ${file} NAME_WE)
-        string(REGEX REPLACE "unit-([^$]+)" "test-\\1" test_name ${file_basename})
+        string(REGEX REPLACE "unit-(.+)" "test-\\1" test_name ${file_basename})
     else()
         set(test_name ${args_NAME})
-        if(NOT test_name MATCHES "test-[^$]+")
+        if(NOT test_name MATCHES "test-.+")
             message(FATAL_ERROR "Test name must start with 'test-'.")
         endif()
     endif()

docs/README.md

@@ -2,12 +2,12 @@
 
 ## Generate documentation
 
-Note on documentation: The source files contain links to the online documentation at https://json.nlohmann.me. This URL
-contains the most recent documentation and should also be applicable to previous versions; documentation for deprecated
-functions is not removed, but marked deprecated.
+Note on documentation: The source files contain links to the online documentation at https://json.nlohmann.me.  
+This URL provides the most recent documentation and also applies to previous versions. Documentation for deprecated
+functions is not removed; instead, it is marked as deprecated.
 
-If you want to see the documentation for a specific tag or commit hash, you can generate it as follows (here for tag
-`v3.10.2`):
+If you want to view the documentation for a specific tag or commit hash, you can generate it locally as follows (example
+using tag `v3.10.2`):
 
 ```shell
 git clone https://github.com/nlohmann/json.git
@@ -16,5 +16,8 @@ git checkout v3.10.2
 make install_venv serve -C docs/mkdocs
 ```
 
-Open URL <http://127.0.0.1:8000/> in your browser. Replace from any URL from the source code `https://json.nlohmann.me`
-with `http://127.0.0.1:8000` to see the documentation for your tag or commit hash.
+Open <http://127.0.0.1:8000/> in your browser. Replace any URL in the source code that points to
+`https://json.nlohmann.me` with `http://127.0.0.1:8000` to view the documentation for the selected tag or commit hash.
+
+
+

docs/mkdocs/docs/api/adl_serializer/from_json.md

@@ -30,14 +30,15 @@ class (either explicitly or via the conversion operators).
 
 ## Return value
 
-Copy of the JSON value, converted to `ValueType`
+1. (none) -- the converted value is written to the output parameter `val`.
+2. the JSON value `j` converted to `TargetType`
 
 ## Examples
 
 ??? example "Example: (1) Default-constructible type"
 
     The example below shows how a `from_json` function can be implemented for a user-defined type. This function is
-    called by the `adl_serializer` when `template get<ns::person>()` is called.
+    called by the `adl_serializer` when `get<ns::person>()` is called.
         
     ```cpp
     --8<-- "examples/from_json__default_constructible.cpp"

docs/mkdocs/docs/api/adl_serializer/index.md

@@ -8,7 +8,7 @@ struct adl_serializer;
 Serializer that uses ADL ([Argument-Dependent Lookup](https://en.cppreference.com/w/cpp/language/adl)) to choose
 `to_json`/`from_json` functions from the types' namespaces.
 
-It is implemented similar to
+It is implemented similarly to
 
 ```cpp
 template<typename ValueType>

docs/mkdocs/docs/api/basic_json/accept.md

@@ -4,12 +4,14 @@
 // (1)
 template<typename InputType>
 static bool accept(InputType&& i,
-                   const bool ignore_comments = false);
+                   const bool ignore_comments = false,
+                   const bool ignore_trailing_commas = false);
 
 // (2)
 template<typename IteratorType>
 static bool accept(IteratorType first, IteratorType last,
-                   const bool ignore_comments = false);
+                   const bool ignore_comments = false,
+                   const bool ignore_trailing_commas = false);
 ```
 
 Checks whether the input is valid JSON.
@@ -50,6 +52,10 @@ Unlike the [`parse()`](parse.md) function, this function neither throws an excep
 :   whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
     (`#!cpp false`); (optional, `#!cpp false` by default)
 
+`ignore_trailing_commas` (in)
+:   whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
+    (`#!cpp false`); (optional, `#!cpp false` by default)
+
 `first` (in)
 :   iterator to the start of the character range
 
@@ -95,6 +101,7 @@ A UTF-8 byte order mark is silently ignored.
 ## See also
 
 - [parse](parse.md) - deserialize from a compatible input
+- [sax_parse](sax_parse.md) - parse input using the SAX interface
 - [operator>>](../operator_gtgt.md) - deserialize from stream
 
 ## Version history
@@ -102,6 +109,7 @@ A UTF-8 byte order mark is silently ignored.
 - Added in version 3.0.0.
 - Ignoring comments via `ignore_comments` added in version 3.9.0.
 - Changed [runtime assertion](../../features/assertions.md) in case of `FILE*` null pointers to exception in version 3.12.0.
+- Added `ignore_trailing_commas` in version 3.12.x.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json/at.md

@@ -82,6 +82,8 @@ Strong exception safety: if an exception occurs, the original value stays intact
       key of an object which cannot be found. See the example below.
     - Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if the JSON pointer `ptr` can
       not be resolved. See the example below.
+    - Throws [`out_of_range.410`](../../home/exceptions.md#jsonexceptionout_of_range410) if an array index in the passed
+      JSON pointer `ptr` exceeds the range of `size_type` (e.g., on 32-bit platforms).
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json/basic_json.md

@@ -74,7 +74,7 @@ basic_json(basic_json&& other) noexcept;
     - **boolean**: `boolean_t` / `bool` can be used.
     - **binary**: `binary_t` / `std::vector<uint8_t>` may be used; unfortunately because string literals cannot be
      distinguished from binary character arrays by the C++ type system, all types compatible with `const char*` will be
-     directed to the string constructor instead. This is both for backwards compatibility, and due to the fact that a
+     directed to the string constructor instead. This is both for backwards compatibility and due to the fact that a
      binary type is not a standard JSON type.
     
     See the examples below.

docs/mkdocs/docs/api/basic_json/boolean_t.md

@@ -9,7 +9,7 @@ The type used to store JSON booleans.
 [RFC 8259](https://tools.ietf.org/html/rfc8259) implicitly describes a boolean as a type which differentiates the two
 literals `#!json true` and `#!json false`.
 
-To store objects in C++, a type is defined by the template parameter  `BooleanType` which chooses the type to use.
+To store boolean values in C++, a type is defined by the template parameter  `BooleanType` which chooses the type to use.
 
 ## Notes
 

docs/mkdocs/docs/api/basic_json/contains.md

@@ -48,11 +48,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
 
 1. The function does not throw exceptions.
 2. The function does not throw exceptions.
-3. The function can throw the following exceptions:
-    - Throws [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) if an array index begins with
-      `0`.
-    - Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) if an array index was not a
-      number.
+3. The function does not throw exceptions.
 
 ## Complexity
 
@@ -111,6 +107,11 @@ Logarithmic in the size of the JSON object.
     --8<-- "examples/contains__json_pointer.output"
     ```
 
+## See also
+
+- [find](find.md) find a value in an object
+- [count](count.md) returns the number of occurrences of a key
+
 ## Version history
 
 1. Added in version 3.11.0.

docs/mkdocs/docs/api/basic_json/count.md

@@ -72,6 +72,11 @@ This method always returns `0` when executed on a JSON type that is not an objec
     --8<-- "examples/count__keytype.c++17.output"
     ```
 
+## See also
+
+- [find](find.md) find a value in an object
+- [contains](contains.md) checks whether a key exists
+
 ## Version history
 
 1. Added in version 3.11.0.

docs/mkdocs/docs/api/basic_json/crbegin.md

@@ -10,7 +10,7 @@ Returns an iterator to the reverse-beginning; that is, the last element.
 
 ## Return value
 
-reverse iterator to the first element
+reverse iterator to the last element
 
 ## Exception safety
 

docs/mkdocs/docs/api/basic_json/crend.md

@@ -25,7 +25,7 @@ Constant.
 
 ??? example
 
-    The following code shows an example for `eend()`.
+    The following code shows an example for `crend()`.
     
     ```cpp
     --8<-- "examples/crend.cpp"

docs/mkdocs/docs/api/basic_json/diff.md

@@ -56,6 +56,9 @@ Currently, only `remove`, `add`, and `replace` operations are generated.
 ## See also
 
 - [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
+- [patch](patch.md) applies a JSON Patch
+- [patch_inplace](patch_inplace.md) applies a JSON Patch in place
+- [merge_patch](merge_patch.md) applies a JSON Merge Patch
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json/dump.md

@@ -26,9 +26,9 @@ and `ensure_ascii` parameters.
 
 `error_handler` (in)
 :   how to react on decoding errors; there are three possible values (see [`error_handler_t`](error_handler_t.md):
-    `strict` (throws and exception in case a decoding error occurs; default), `replace` (replace invalid UTF-8 sequences
-    with U+FFFD), and `ignore` (ignore invalid UTF-8 sequences during serialization; all bytes are copied to the output
-    unchanged)).
+    `strict` (throws an exception in case a decoding error occurs; default), `replace` (replace invalid UTF-8 sequences
+    with U+FFFD), and `ignore` (ignore invalid UTF-8 sequences during serialization; all valid bytes are copied to the
+    output unchanged, and invalid bytes are dropped)).
     
 ## Return value
 
@@ -71,6 +71,11 @@ Binary values are serialized as an object containing two keys:
     --8<-- "examples/dump.output"
     ```
 
+## See also
+
+- [to_string](to_string.md) returns a string representation of a JSON value
+- [operator<<](../operator_ltlt.md) serialize to stream
+
 ## Version history
 
 - Added in version 1.0.0.

docs/mkdocs/docs/api/basic_json/emplace.md

@@ -29,6 +29,10 @@ iterators (including the `end()` iterator) and all references to the elements ar
 a pair consisting of an iterator to the inserted element, or the already-existing element if no insertion happened, and
 a `#!cpp bool` denoting whether the insertion took place.
 
+## Exception safety
+
+Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
+
 ## Exceptions
 
 Throws [`type_error.311`](../../home/exceptions.md#jsonexceptiontype_error311) when called on a type other than JSON
@@ -56,6 +60,11 @@ Logarithmic in the size of the container, O(log(`size()`)).
     --8<-- "examples/emplace.output"
     ```
 
+## See also
+
+- [emplace_back](emplace_back.md) add a value to an array
+- [insert](insert.md) add values to an array/object
+
 ## Version history
 
 - Since version 2.0.8.

docs/mkdocs/docs/api/basic_json/empty.md

@@ -4,7 +4,7 @@
 bool empty() const noexcept;
 ```
 
-Checks if a JSON value has no elements (i.e. whether its [`size()`](size.md) is `0`).
+Checks if a JSON value has no elements (i.e., whether its [`size()`](size.md) is `0`).
     
 ## Return value
 

docs/mkdocs/docs/api/basic_json/erase.md

@@ -101,7 +101,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
 4. See 3.
 5. The function can throw the following exceptions:
     - Throws [`type_error.307`](../../home/exceptions.md#jsonexceptiontype_error307) when called on a type other than
-      JSON object; example: `"cannot use erase() with null"`
+      JSON array; example: `"cannot use erase() with null"`
     - Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) when `idx >= size()`; example:
       `"array index 17 is out of range"`
 
@@ -202,6 +202,11 @@ Strong exception safety: if an exception occurs, the original value stays intact
     --8<-- "examples/erase__size_type.output"
     ```
 
+## See also
+
+- [clear](clear.md) clears the contents
+- [insert](insert.md) add values to an array/object
+
 ## Version history
 
 1. Added in version 1.0.0. Added support for binary types in version 3.8.0.

docs/mkdocs/docs/api/basic_json/error_handler_t.md

@@ -18,7 +18,7 @@ replace
 :   replace invalid UTF-8 sequences with U+FFFD (� REPLACEMENT CHARACTER)
 
 ignore
-:   ignore invalid UTF-8 sequences; all bytes are copied to the output unchanged
+:   ignore invalid UTF-8 sequences; all valid bytes are copied to the output unchanged, and invalid bytes are dropped
 
 ## Examples
 

docs/mkdocs/docs/api/basic_json/find.md

@@ -78,6 +78,7 @@ This method always returns `end()` when executed on a JSON type that is not an o
 
 ## See also
 
+- [count](count.md) returns the number of occurrences of a key
 - [contains](contains.md) checks whether a key exists
 
 ## Version history

docs/mkdocs/docs/api/basic_json/format_as.md

@@ -0,0 +1,94 @@
+# format_as(basic_json)
+
+```cpp
+template <typename BasicJsonType>
+std::string format_as(const BasicJsonType& j);
+```
+
+This function implements the [`format_as`](https://fmt.dev/latest/api/#formatting-user-defined-types)
+customization point used by the [{fmt}](https://github.com/fmtlib/fmt) library (fmtlib). It has no
+dependency on any `fmt` header and no effect at all unless a caller's translation unit also includes
+`fmt` and calls `fmt::format`/`fmt::print` on a JSON value.
+
+## Template parameters
+
+`BasicJsonType`
+:   a specialization of [`basic_json`](index.md)
+
+## Return value
+
+string containing the serialization of the JSON value (same as [`dump()`](dump.md))
+
+## Exception safety
+
+Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
+
+## Exceptions
+
+Throws [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) if a string stored inside the JSON value
+is not UTF-8 encoded
+
+## Complexity
+
+Linear.
+
+## Possible implementation
+
+```cpp
+template <typename BasicJsonType>
+std::string format_as(const BasicJsonType& j)
+{
+    return j.dump();
+}
+```
+
+## Notes
+
+!!! warning "Version-dependent effect on fmt"
+
+    `fmt` only picks up a `format_as` overload that returns a `std::string` in fmt **10.0.0 through
+    11.0.2**. Starting with fmt **11.1.0**, `fmt` restricts automatic `format_as` pickup to overloads that
+    return an arithmetic type, so this function has no effect there (it is simply unused, not a compile
+    error).
+
+    If you use fmt \>= 11.1.0, or want the same pretty-print spec support that
+    [`std::formatter<basic_json>`](std_formatter.md) has (`#!cpp "{:#}"`, a width to set the indent such
+    as `#!cpp "{:2}"`/`#!cpp "{:#2}"`, and fill-and-align to pick the indent character such as
+    `#!cpp "{:.>#}"`), define your own `fmt::formatter` specialization mirroring the same logic:
+
+    ```cpp
+    --8<-- "../../../tests/fmt_formatter/project/main.cpp:formatter_recipe"
+    ```
+
+    This recipe isn't shipped by the library itself, since doing so would make `fmt` a build dependency
+    (see the FAQ entry on
+    [using JSON values with `std::format` or `fmt`](../../home/faq.md#using-json-values-with-stdformat-or-fmt)
+    for more background) — but it *is* compiled and exercised against a real, current `fmt` release as
+    part of the library's own test suite (`tests/fmt_formatter`, via CMake `FetchContent`), so it's kept in
+    sync with `std::formatter<basic_json>` and verified to actually work, not just illustrative.
+
+## Examples
+
+??? example
+
+    The following code shows how the library's `format_as()` function integrates with `fmt::format`,
+    allowing argument-dependent lookup.
+
+    ```cpp
+    --8<-- "examples/format_as.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/format_as.output"
+    ```
+
+## See also
+
+- [dump](dump.md)
+- [std::formatter<basic_json>](std_formatter.md) - the `std::format` (C++20) equivalent
+
+## Version history
+
+- Added in version 3.12.x.

docs/mkdocs/docs/api/basic_json/from_bjdata.md

@@ -67,6 +67,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs
 - Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a string could not be parsed
   successfully
+- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the size of an optimized container
+  or n-dimensional array cannot be represented by `std::size_t`
 
 ## Complexity
 
@@ -88,6 +90,14 @@ Linear in the size of the input.
     --8<-- "examples/from_bjdata.output"
     ```
 
+## See also
+
+- [to_bjdata](to_bjdata.md) create a BJData serialization of a JSON value
+- [from_cbor](from_cbor.md) create a JSON value from an input in CBOR format
+- [from_msgpack](from_msgpack.md) create a JSON value from an input in MessagePack format
+- [from_bson](from_bson.md) create a JSON value from an input in BSON format
+- [from_ubjson](from_ubjson.md) create a JSON value from an input in UBJSON format
+
 ## Version history
 
 - Added in version 3.11.0.

docs/mkdocs/docs/api/basic_json/from_bson.md

@@ -62,8 +62,12 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 
 ## Exceptions
 
-Throws [`parse_error.114`](../../home/exceptions.md#jsonexceptionparse_error114) if an unsupported BSON record type is
-encountered.
+- Throws [`parse_error.110`](../../home/exceptions.md#jsonexceptionparse_error110) if the given input ends prematurely or
+  the end of the input was not reached when `strict` was set to true
+- Throws [`parse_error.112`](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs (e.g., an
+  invalid string or byte array length)
+- Throws [`parse_error.114`](../../home/exceptions.md#jsonexceptionparse_error114) if an unsupported BSON record type is
+  encountered
 
 ## Complexity
 
@@ -92,6 +96,7 @@ Linear in the size of the input.
 - [from_cbor](from_cbor.md) for the related CBOR format
 - [from_msgpack](from_msgpack.md) for the related MessagePack format
 - [from_ubjson](from_ubjson.md) for the related UBJSON format
+- [from_bjdata](from_bjdata.md) for the related BJData format
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json/from_cbor.md

@@ -96,6 +96,14 @@ Linear in the size of the input.
     --8<-- "examples/from_cbor.output"
     ```
 
+## See also
+
+- [to_cbor](to_cbor.md) create a CBOR serialization of a JSON value
+- [from_msgpack](from_msgpack.md) create a JSON value from an input in MessagePack format
+- [from_bson](from_bson.md) create a JSON value from an input in BSON format
+- [from_ubjson](from_ubjson.md) create a JSON value from an input in UBJSON format
+- [from_bjdata](from_bjdata.md) create a JSON value from an input in BJData format
+
 ## Version history
 
 - Added in version 2.0.9.

docs/mkdocs/docs/api/basic_json/from_msgpack.md

@@ -89,6 +89,14 @@ Linear in the size of the input.
     --8<-- "examples/from_msgpack.output"
     ```
 
+## See also
+
+- [to_msgpack](to_msgpack.md) create a MessagePack serialization of a JSON value
+- [from_cbor](from_cbor.md) create a JSON value from an input in CBOR format
+- [from_bson](from_bson.md) create a JSON value from an input in BSON format
+- [from_ubjson](from_ubjson.md) create a JSON value from an input in UBJSON format
+- [from_bjdata](from_bjdata.md) create a JSON value from an input in BJData format
+
 ## Version history
 
 - Added in version 2.0.9.
@@ -101,7 +109,7 @@ Linear in the size of the input.
     - Overload (2) replaces calls to `from_msgpack` with a pointer and a length as first two parameters, which has been
       deprecated in version 3.8.0. This overload will be removed in version 4.0.0. Please replace all calls like
       `#!cpp from_msgpack(ptr, len, ...);` with `#!cpp from_msgpack(ptr, ptr+len, ...);`.
-    - Overload (2) replaces calls to `from_cbor` with a pair of iterators as their first parameter, which has been
+    - Overload (2) replaces calls to `from_msgpack` with a pair of iterators as their first parameter, which has been
       deprecated in version 3.8.0. This overload will be removed in version 4.0.0. Please replace all calls like
       `#!cpp from_msgpack({ptr, ptr+len}, ...);` with `#!cpp from_msgpack(ptr, ptr+len, ...);`.
 

docs/mkdocs/docs/api/basic_json/from_ubjson.md

@@ -65,8 +65,10 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [parse_error.110](../../home/exceptions.md#jsonexceptionparse_error110) if the given input ends prematurely or
   the end of the file was not reached when `strict` was set to true
 - Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs
-- Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a string could not be parsed 
+- Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a string could not be parsed
   successfully
+- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the size of an optimized container
+  or n-dimensional array cannot be represented by `std::size_t`
 
 ## Complexity
 
@@ -88,6 +90,14 @@ Linear in the size of the input.
     --8<-- "examples/from_ubjson.output"
     ```
 
+## See also
+
+- [to_ubjson](to_ubjson.md) create a UBJSON serialization of a JSON value
+- [from_cbor](from_cbor.md) create a JSON value from an input in CBOR format
+- [from_msgpack](from_msgpack.md) create a JSON value from an input in MessagePack format
+- [from_bson](from_bson.md) create a JSON value from an input in BSON format
+- [from_bjdata](from_bjdata.md) create a JSON value from an input in BJData format
+
 ## Version history
 
 - Added in version 3.1.0.

docs/mkdocs/docs/api/basic_json/get.md

@@ -88,12 +88,32 @@ constexpr const PointerType get_ptr() const noexcept;
 
 Depends on what `json_serializer<ValueType>` `from_json()` method throws
 
+## Complexity
+
+Depends on the `json_serializer<ValueType>::from_json()` implementation for overloads (1) and (2); constant for
+overload (3).
+
 ## Notes
 
-!!! danger "Undefined behavior"
+!!! danger "Undefined behavior for pointers"
 
     Writing data to the pointee (overload 3) of the result yields an undefined state.
 
+!!! danger "Undefined behavior for numeric conversions"
+
+    Conversions between numeric types are performed by the corresponding
+    `from_json()` implementation using the target C++ type. When converting
+    between numeric types, the library does not check whether the source
+    value is representable by the target type.
+    
+    If the source value is outside the range of the target type, the behavior
+    is the same as the corresponding C++ conversion. In particular, converting
+    a floating-point value to an integer type that cannot represent the value
+    results in undefined behavior.
+
+    See [Number conversion](../../features/types/number_handling.md#number-conversion)
+    for more information.
+
 ## Examples
 
 ??? example
@@ -129,6 +149,13 @@ Depends on what `json_serializer<ValueType>` `from_json()` method throws
     --8<-- "examples/get__PointerType.output"
     ```
 
+## See also
+
+- [get_to](get_to.md) convert and write into a passed value
+- [get_ptr](get_ptr.md) get a pointer to the stored value
+- [get_ref](get_ref.md) get a reference to the stored value
+- [operator ValueType](operator_ValueType.md) get a value via implicit conversion
+
 ## Version history
 
 1. Since version 2.1.0.

docs/mkdocs/docs/api/basic_json/get_binary.md

@@ -40,6 +40,11 @@ Constant.
     --8<-- "examples/get_binary.output"
     ```
 
+## See also
+
+- [get](get.md) get a value (explicit conversion)
+- [get_ref](get_ref.md) get a reference to the stored value
+
 ## Version history
 
 - Added in version 3.8.0.

docs/mkdocs/docs/api/basic_json/get_to.md

@@ -34,6 +34,10 @@ the input parameter, allowing chaining calls
 
 Depends on what `json_serializer<ValueType>` `from_json()` method throws
 
+## Complexity
+
+Depends on the `json_serializer<ValueType>::from_json()` implementation.
+
 ## Examples
 
 ??? example
@@ -53,6 +57,12 @@ Depends on what `json_serializer<ValueType>` `from_json()` method throws
     --8<-- "examples/get_to.output"
     ```
 
+## See also
+
+- [get](get.md) get a value (explicit conversion)
+- [get_ref](get_ref.md) get a reference to the stored value
+- [get_ptr](get_ptr.md) get a pointer to the stored value
+
 ## Version history
 
 - Since version 3.3.0.

docs/mkdocs/docs/api/basic_json/index.md

@@ -301,6 +301,7 @@ Access to the JSON value
 - [**operator<<(std::ostream&)**](../operator_ltlt.md) - serialize to stream
 - [**operator>>(std::istream&)**](../operator_gtgt.md) - deserialize from stream
 - [**to_string**](to_string.md) - user-defined `to_string` function for JSON values
+- [**format_as**](format_as.md) - user-defined `format_as` function for JSON values (fmt support)
 
 ## Literals
 
@@ -308,6 +309,7 @@ Access to the JSON value
 
 ## Helper classes
 
+- [**std::formatter&lt;basic_json&gt;**](std_formatter.md) - make JSON values formattable with `std::format`
 - [**std::hash&lt;basic_json&gt;**](std_hash.md) - return a hash value for a JSON object
 - [**std::swap&lt;basic_json&gt;**](std_swap.md) - exchanges the values of two JSON objects
 

docs/mkdocs/docs/api/basic_json/insert.md

@@ -29,11 +29,11 @@ void insert(const_iterator first, const_iterator last);
 For all cases where an element is added to an **array**, a reallocation can happen, in which case all iterators
 (including the [`end()`](end.md) iterator) and all references to the elements are invalidated. Otherwise, only the
 [`end()`](end.md) iterator is invalidated. Also, any iterator or reference after the insertion point will point to the
-same index which is now a different value.
+same index, which is now a different value.
 
 For [`ordered_json`](../ordered_json.md), also adding an element to an **object** can yield a reallocation which again
 invalidates all iterators and all references. Also, any iterator or reference after the insertion point will point to
-the same index which is now a different value.
+the same index, which is now a different value.
 
 ## Parameters
 
@@ -96,8 +96,8 @@ Strong exception safety: if an exception occurs, the original value stays intact
 5. The function can throw the following exceptions:
     - Throws [`type_error.309`](../../home/exceptions.md#jsonexceptiontype_error309) if called on JSON values other than
       objects; example: `"cannot use insert() with string"`
-    - Throws [`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) if called on an
-      iterator which does not belong to the current JSON value; example: `"iterator does not fit current value"`
+    - Throws [`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) if `first` or `last`
+      do not point to an object; example: `"iterators first and last must point to objects"`
     - Throws [`invalid_iterator.210`](../../home/exceptions.md#jsonexceptioninvalid_iterator210) if `first` and `last`
       do not belong to the same JSON value; example: `"iterators do not fit"`
 
@@ -181,6 +181,13 @@ Strong exception safety: if an exception occurs, the original value stays intact
     --8<-- "examples/insert__range_object.output"
     ```
 
+## See also
+
+- [emplace](emplace.md) add a value to an object
+- [emplace_back](emplace_back.md) add a value to an array
+- [push_back](push_back.md) add a value to an array/object
+- [update](update.md) merges objects
+
 ## Version history
 
 1. Added in version 1.0.0.

docs/mkdocs/docs/api/basic_json/invalid_iterator.md

@@ -66,6 +66,7 @@ classDiagram
 
 ## See also
 
+- [`exception`](exception.md) for the base class of all exceptions thrown by the library
 - [List of iterator errors](../../home/exceptions.md#iterator-errors)
 - [`parse_error`](parse_error.md) for exceptions indicating a parse error
 - [`type_error`](type_error.md) for exceptions indicating executing a member function with a wrong type

docs/mkdocs/docs/api/basic_json/is_discarded.md

@@ -45,11 +45,13 @@ Constant.
 
     When a value is discarded by a callback function (see [`parser_callback_t`](parser_callback_t.md)) during parsing,
     then it is removed when it is part of a structured value. For instance, if the second value of an array is discarded,
-    instead of `#!json [null, discarded, false]`, the array `#!json [null, false]` is returned. Only if the top-level
-    value is discarded, the return value of the `parse` call is discarded.
+    instead of `#!json [null, discarded, false]`, the array `#!json [null, false]` is returned. If the top-level value
+    itself is discarded by the callback, the `parse` call returns a `#!json null` value.
 
-This function will always be `#!cpp false` for JSON values after parsing. That is, discarded values can only occur
-during parsing, but will be removed when inside a structured value or replaced by null in other cases.
+After a successful parse, this function always returns `#!cpp false`: discarded values can only occur during parsing and
+are either removed when inside a structured value or replaced by `#!json null` at the top level. The exception is parsing
+with `allow_exceptions` set to `#!cpp false`: a parse error then yields a discarded value for which this function returns
+`#!cpp true` (see [`parse`](parse.md)).
 
 ## Examples
 

docs/mkdocs/docs/api/basic_json/is_number.md

@@ -9,7 +9,7 @@ unsigned) and floating-point values.
     
 ## Return value
 
-`#!cpp true` if type is number (regardless whether integer, unsigned integer, or floating-type), `#!cpp false` otherwise.
+`#!cpp true` if type is number (regardless whether integer, unsigned integer, or floating-point), `#!cpp false` otherwise.
 
 ## Exception safety
 

docs/mkdocs/docs/api/basic_json/items.md

@@ -84,6 +84,11 @@ When iterating over an array, `key()` will return the index of the element as st
     --8<-- "examples/items.output"
     ```
 
+## See also
+
+- [begin](begin.md) returns an iterator to the first element
+- [end](end.md) returns an iterator to one past the last element
+
 ## Version history
 
 - Added `iterator_wrapper` in version 3.0.0.

docs/mkdocs/docs/api/basic_json/json_base_class_t.md

@@ -16,7 +16,7 @@ Examples of such functionality might be metadata, additional member functions (e
 
 #### Default type
 
-The default value for `CustomBaseClass` is `void`. In this case an
+The default value for `CustomBaseClass` is `void`. In this case, an
 [empty base class](https://en.cppreference.com/w/cpp/language/ebo) is used and no additional functionality is injected.
 
 #### Limitations

docs/mkdocs/docs/api/basic_json/meta.md

@@ -13,7 +13,7 @@ JSON object holding version information
 
 | key         | description                                                                                                                                                                                                                                                                    |
 |-------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| `compiler`  | Information on the used compiler. It is an object with the following keys: `c++` (the used C++ standard), `family` (the compiler family; possible values are `clang`, `icc`, `gcc`, `ilecpp`, `msvc`, `pgcpp`, `sunpro`, and `unknown`), and `version` (the compiler version). |
+| `compiler`  | Information on the used compiler. It is an object with the following keys: `c++` (the used C++ standard), `family` (the compiler family; possible values are `clang`, `icc`, `gcc`, `ilecpp`, `msvc`, `pgcpp`, `sunpro`, and `unknown`), and `version` (the compiler version). On HP aCC compilers, `compiler` is instead the plain string `hp`. |
 | `copyright` | The copyright line for the library as string.                                                                                                                                                                                                                                  |
 | `name`      | The name of the library as string.                                                                                                                                                                                                                                             |
 | `platform`  | The used platform as string. Possible values are `win32`, `linux`, `apple`, `unix`, and `unknown`.                                                                                                                                                                             |

docs/mkdocs/docs/api/basic_json/number_integer_t.md

@@ -32,7 +32,6 @@ With the default values for `NumberIntegerType` (`std::int64_t`), the default va
 - The restrictions about leading zeros are not enforced in C++. Instead, leading zeros in integer literals lead to an
   interpretation as an octal number. Internally, the value will be stored as a decimal number. For instance, the C++
   integer literal `010` will be serialized to `8`. During deserialization, leading zeros yield an error.
-- Not-a-number (NaN) values will be serialized to `null`.
 
 #### Limits
 

docs/mkdocs/docs/api/basic_json/number_unsigned_t.md

@@ -32,7 +32,6 @@ With the default values for `NumberUnsignedType` (`std::uint64_t`), the default
 - The restrictions about leading zeros are not enforced in C++. Instead, leading zeros in integer literals lead to an
   interpretation as an octal number. Internally, the value will be stored as a decimal number. For instance, the C++
   integer  literal `010` will be serialized to `8`. During deserialization, leading zeros yield an error.
-- Not-a-number (NaN) values will be serialized to `null`.
 
 #### Limits
 
@@ -45,7 +44,7 @@ when used in a constructor. During deserialization, too large or small integer n
 as [`number_integer_t`](number_integer_t.md) or [`number_float_t`](number_float_t.md).
 
 [RFC 8259](https://tools.ietf.org/html/rfc8259) further states:
-> Note that when such software is used, numbers that are integers and are in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are
+> Note that when such software is used, numbers that are integers and are in the range $[-2^{53}+1, 2^{53}-1]$ are
 > interoperable in the sense that implementations will agree exactly on their numeric values.
 
 As this range is a subrange (when considered in conjunction with the `number_integer_t` type) of the exactly supported

docs/mkdocs/docs/api/basic_json/operator+=.md

@@ -50,9 +50,12 @@ invalidates all iterators and all references.
 
 ## Exceptions
 
-All functions can throw the following exception:
-  - Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
-    JSON array or null; example: `"cannot use operator+=() with number"`
+1. Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
+   JSON array or null; example: `"cannot use push_back() with number"`
+2. Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
+   JSON object or null; example: `"cannot use push_back() with number"`
+3. Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
+   JSON array or null; example: `"cannot use push_back() with number"`
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json/operator=.md

@@ -5,7 +5,8 @@ basic_json& operator=(basic_json other) noexcept (
     std::is_nothrow_move_constructible<value_t>::value &&
     std::is_nothrow_move_assignable<value_t>::value &&
     std::is_nothrow_move_constructible<json_value>::value &&
-    std::is_nothrow_move_assignable<json_value>::value
+    std::is_nothrow_move_assignable<json_value>::value &&
+    std::is_nothrow_move_assignable<json_base_class_t>::value
 );
 ```
 
@@ -17,6 +18,10 @@ constructor, destructor, and the `swap()` member function.
 `other` (in)
 :   value to copy from
 
+## Exception safety
+
+Strong guarantee: if an exception is thrown while copying `other`, there are no changes to `#!cpp *this`.
+
 ## Complexity
 
 Linear.
@@ -38,6 +43,11 @@ Linear.
     --8<-- "examples/basic_json__copyassignment.output"
     ```
 
+## See also
+
+- [basic_json](basic_json.md) create a JSON value
+- [swap](swap.md) exchanges the contents of two JSON values
+
 ## Version history
 
 - Added in version 1.0.0.

docs/mkdocs/docs/api/basic_json/operator[].md

@@ -83,6 +83,8 @@ Strong exception safety: if an exception occurs, the original value stays intact
       in the passed JSON pointer `ptr` for the const version.
     - Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if the JSON pointer `ptr` can
       not be resolved.
+    - Throws [`out_of_range.410`](../../home/exceptions.md#jsonexceptionout_of_range410) if an array index in the passed
+      JSON pointer `ptr` exceeds the range of `size_type` (e.g., on 32-bit platforms).
 
 ## Complexity
 
@@ -95,7 +97,10 @@ Strong exception safety: if an exception occurs, the original value stays intact
 
 !!! danger "Undefined behavior and runtime assertions"
 
-    1. If the element with key `idx` does not exist, the behavior is undefined.
+    The following cases apply to the **const** overloads; the non-const overloads instead insert the missing element
+    (see the notes below).
+
+    1. If the element at index `idx` does not exist, the behavior is undefined.
     2. If the element with key `key` does not exist, the behavior is undefined and is **guarded by a
        [runtime assertion](../../features/assertions.md)**!
 

docs/mkdocs/docs/api/basic_json/operator_ValueType.md

@@ -75,6 +75,10 @@ Linear in the size of the JSON value.
     --8<-- "examples/operator__ValueType.output"
     ```
 
+## See also
+
+- [get](get.md) get a value (explicit conversion)
+
 ## Version history
 
 - Since version 1.0.0.

docs/mkdocs/docs/api/basic_json/operator_eq.md

@@ -20,7 +20,7 @@ class basic_json {
 ```
 
 1. Compares two JSON values for equality according to the following rules:
-    - Two JSON values are equal if (1) neither value is discarded, or (2) they are of the same type and their stored
+    - Two JSON values are equal if (1) neither value is discarded, and (2) they are of the same type and their stored
       values are the same according to their respective `operator==`.
     - Integer and floating-point numbers are automatically converted before comparison.
 
@@ -79,13 +79,13 @@ Linear.
     }
     ```
     
-    Or you can self-defined operator equal function like this:
+    Or you can define your own equality function like this:
     
     ```cpp
     bool my_equal(const_reference lhs, const_reference rhs)
     {
-        const auto lhs_type lhs.type();
-        const auto rhs_type rhs.type();
+        const auto lhs_type = lhs.type();
+        const auto rhs_type = rhs.type();
         if (lhs_type == rhs_type)
         {
             switch(lhs_type)
@@ -162,6 +162,11 @@ Linear.
     --8<-- "examples/operator__equal__nullptr_t.output"
     ```
 
+## See also
+
+- [operator!=](operator_ne.md) compare for inequality
+- [operator<=>](operator_spaceship.md) comparison: 3-way (C++20)
+
 ## Version history
 
 1. Added in version 1.0.0. Added C++20 member functions in version 3.11.0.

docs/mkdocs/docs/api/basic_json/operator_ge.md

@@ -35,7 +35,7 @@ bool operator>=(ScalarType lhs, const const_reference rhs) noexcept;  // (2)
 
 ## Return value
 
-whether `lhs` is less than or equal to `rhs`
+whether `lhs` is greater than or equal to `rhs`
 
 ## Exception safety
 

docs/mkdocs/docs/api/basic_json/other_error.md

@@ -66,6 +66,7 @@ classDiagram
 
 ## See also
 
+- [`exception`](exception.md) for the base class of all exceptions thrown by the library
 - [List of other errors](../../home/exceptions.md#further-exceptions)
 - [`parse_error`](parse_error.md) for exceptions indicating a parse error
 - [`invalid_iterator`](invalid_iterator.md) for exceptions indicating errors with iterators

docs/mkdocs/docs/api/basic_json/out_of_range.md

@@ -67,6 +67,7 @@ classDiagram
 
 ## See also
 
+- [`exception`](exception.md) for the base class of all exceptions thrown by the library
 - [List of out-of-range errors](../../home/exceptions.md#out-of-range)
 - [`parse_error`](parse_error.md) for exceptions indicating a parse error
 - [`invalid_iterator`](invalid_iterator.md) for exceptions indicating errors with iterators

docs/mkdocs/docs/api/basic_json/parse.md

@@ -6,14 +6,16 @@ template<typename InputType>
 static basic_json parse(InputType&& i,
                         const parser_callback_t cb = nullptr,
                         const bool allow_exceptions = true,
-                        const bool ignore_comments = false);
+                        const bool ignore_comments = false,
+                        const bool ignore_trailing_commas = false);
 
 // (2)
 template<typename IteratorType>
 static basic_json parse(IteratorType first, IteratorType last,
                         const parser_callback_t cb = nullptr,
                         const bool allow_exceptions = true,
-                        const bool ignore_comments = false);
+                        const bool ignore_comments = false,
+                        const bool ignore_trailing_commas = false);
 ```
 
 1. Deserialize from a compatible input.
@@ -56,6 +58,10 @@ static basic_json parse(IteratorType first, IteratorType last,
 :   whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
     (`#!cpp false`); (optional, `#!cpp false` by default)
 
+`ignore_trailing_commas` (in)
+:   whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
+    (`#!cpp false`); (optional, `#!cpp false` by default)
+
 `first` (in)
 :   iterator to the start of a character range
 
@@ -75,9 +81,6 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 
 - Throws [`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101) in case of an unexpected token, or
   empty input like a null `FILE*` or `char*` pointer.
-- Throws [`parse_error.102`](../../home/exceptions.md#jsonexceptionparse_error102) if `to_unicode` fails or surrogate
-  error.
-- Throws [`parse_error.103`](../../home/exceptions.md#jsonexceptionparse_error103) if `to_unicode` fails.
 
 ## Complexity
 
@@ -89,6 +92,9 @@ super-linear complexity.
 
 A UTF-8 byte order mark is silently ignored.
 
+Invalid Unicode escapes and unpaired surrogates in the input are reported as
+[`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101) with a detailed message.
+
 ## Examples
 
 ??? example "Parsing from a character array"
@@ -177,7 +183,7 @@ A UTF-8 byte order mark is silently ignored.
 
 ??? example "Effect of `allow_exceptions` parameter"
 
-    The example below demonstrates the effect of the `allow_exceptions` parameter in the ´parse()` function.
+    The example below demonstrates the effect of the `allow_exceptions` parameter in the `parse()` function.
 
     ```cpp
     --8<-- "examples/parse__allow_exceptions.cpp"
@@ -189,9 +195,38 @@ A UTF-8 byte order mark is silently ignored.
     --8<-- "examples/parse__allow_exceptions.output"
     ```
 
+??? example "Effect of `ignore_comments` parameter"
+
+    The example below demonstrates the effect of the `ignore_comments` parameter in the `parse()` function.
+
+    ```cpp
+    --8<-- "examples/comments.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/comments.output"
+    ```
+
+??? example "Effect of `ignore_trailing_commas` parameter"
+
+    The example below demonstrates the effect of the `ignore_trailing_commas` parameter in the `parse()` function.
+
+    ```cpp
+    --8<-- "examples/trailing_commas.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/trailing_commas.output"
+    ```
+
 ## See also
 
 - [accept](accept.md) - check if the input is valid JSON
+- [sax_parse](sax_parse.md) - parse input using the SAX interface
 - [operator>>](../operator_gtgt.md) - deserialize from stream
 
 ## Version history
@@ -200,6 +235,7 @@ A UTF-8 byte order mark is silently ignored.
 - Overload for contiguous containers (1) added in version 2.0.3.
 - Ignoring comments via `ignore_comments` added in version 3.9.0.
 - Changed [runtime assertion](../../features/assertions.md) in case of `FILE*` null pointers to exception in version 3.12.0.
+- Added `ignore_trailing_commas` in version 3.12.x.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json/parse_error.md

@@ -75,6 +75,7 @@ or the end of file. This also holds true when reading a byte vector for binary f
 
 ## See also
 
+- [`exception`](exception.md) for the base class of all exceptions thrown by the library
 - [List of parse errors](../../home/exceptions.md#parse-errors)
 - [`invalid_iterator`](invalid_iterator.md) for exceptions indicating errors with iterators
 - [`type_error`](type_error.md) for exceptions indicating executing a member function with a wrong type

docs/mkdocs/docs/api/basic_json/parse_event_t.md

@@ -24,6 +24,11 @@ The parser callback distinguishes the following events:
 
 ![Example when certain parse events are triggered](../../images/callback_events.png)
 
+## See also
+
+- [parser_callback_t](parser_callback_t.md) callback function type for the parser
+- [parse](parse.md) deserialize from a compatible input
+
 ## Version history
 
 - Added in version 1.0.0.

docs/mkdocs/docs/api/basic_json/parser_callback_t.md

@@ -68,6 +68,11 @@ the latter case, it is either skipped completely or replaced by an empty discard
     --8<-- "examples/parse__string__parser_callback_t.output"
     ```
 
+## See also
+
+- [parse](parse.md) deserialize from a compatible input
+- [parse_event_t](parse_event_t.md) enumeration of parser events
+
 ## Version history
 
 - Added in version 1.0.0.

docs/mkdocs/docs/api/basic_json/patch.md

@@ -32,7 +32,9 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
   could not be resolved successfully in the current JSON value; example: `"key baz not found"`.
 - Throws [`out_of_range.405`](../../home/exceptions.md#jsonexceptionout_of_range405) if JSON pointer has no parent
   ("add", "remove", "move")
-- Throws [`out_of_range.501`](../../home/exceptions.md#jsonexceptionother_error501) if "test" operation was
+- Throws [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) if an "add" operation's target
+  location has a parent that is neither an object nor an array.
+- Throws [`other_error.501`](../../home/exceptions.md#jsonexceptionother_error501) if "test" operation was
   unsuccessful.
 
 ## Complexity
@@ -71,3 +73,5 @@ is thrown. In any case, the original value is not changed: the patch is applied
 ## Version history
 
 - Added in version 2.0.0.
+- Added [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) and stopped relying on an internal assertion when an "add" operation's
+  target location has a non-object/non-array parent in version 3.12.x.

docs/mkdocs/docs/api/basic_json/patch_inplace.md

@@ -1,7 +1,7 @@
 # <small>nlohmann::basic_json::</small>patch_inplace
 
 ```cpp
-void patch_inplace(const basic_json& json_patch) const;
+void patch_inplace(const basic_json& json_patch);
 ```
 
 [JSON Patch](http://jsonpatch.com) defines a JSON document structure for expressing a sequence of operations to apply to
@@ -28,7 +28,9 @@ No guarantees, value may be corrupted by an unsuccessful patch operation.
   could not be resolved successfully in the current JSON value; example: `"key baz not found"`.
 - Throws [`out_of_range.405`](../../home/exceptions.md#jsonexceptionout_of_range405) if JSON pointer has no parent
   ("add", "remove", "move")
-- Throws [`out_of_range.501`](../../home/exceptions.md#jsonexceptionother_error501) if "test" operation was
+- Throws [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) if an "add" operation's target
+  location has a parent that is neither an object nor an array.
+- Throws [`other_error.501`](../../home/exceptions.md#jsonexceptionother_error501) if "test" operation was
   unsuccessful.
 
 ## Complexity
@@ -62,9 +64,11 @@ function throws an exception.
 
 - [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
 - [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
-- [patch](patch.md) applies a JSON Merge Patch
+- [patch](patch.md) applies a JSON Patch
 - [merge_patch](merge_patch.md) applies a JSON Merge Patch
 
 ## Version history
 
 - Added in version 3.11.0.
+- Added [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) and stopped relying on an internal assertion when an "add" operation's
+  target location has a non-object/non-array parent in version 3.12.x.

docs/mkdocs/docs/api/basic_json/push_back.md

@@ -46,9 +46,12 @@ invalidates all iterators and all references.
 
 ## Exceptions
 
-All functions can throw the following exception:
-  - Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
-    JSON array or null; example: `"cannot use push_back() with number"`
+1. Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
+   JSON array or null; example: `"cannot use push_back() with number"`
+2. Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
+   JSON object or null; example: `"cannot use push_back() with number"`
+3. Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
+   JSON array or null; example: `"cannot use push_back() with number"`
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json/rbegin.md

@@ -11,7 +11,7 @@ Returns an iterator to the reverse-beginning; that is, the last element.
 
 ## Return value
 
-reverse iterator to the first element
+reverse iterator to the last element
 
 ## Exception safety
 

docs/mkdocs/docs/api/basic_json/rend.md

@@ -26,7 +26,7 @@ Constant.
 
 ??? example
 
-    The following code shows an example for `eend()`.
+    The following code shows an example for `rend()`.
     
     ```cpp
     --8<-- "examples/rend.cpp"

docs/mkdocs/docs/api/basic_json/sax_parse.md

@@ -7,7 +7,8 @@ static bool sax_parse(InputType&& i,
                       SAX* sax,
                       input_format_t format = input_format_t::json,
                       const bool strict = true,
-                      const bool ignore_comments = false);
+                      const bool ignore_comments = false,
+                      const bool ignore_trailing_commas = false);
 
 // (2)
 template<class IteratorType, class SAX>
@@ -15,7 +16,8 @@ static bool sax_parse(IteratorType first, IteratorType last,
                       SAX* sax,
                       input_format_t format = input_format_t::json,
                       const bool strict = true,
-                      const bool ignore_comments = false);
+                      const bool ignore_comments = false,
+                      const bool ignore_trailing_commas = false);
 ```
 
 Read from input and generate SAX events
@@ -41,18 +43,19 @@ The SAX event lister must follow the interface of [`json_sax`](../json_sax/index
       iterators.
 
 `IteratorType`
-:   Description
+:   a compatible iterator type for overload (2); a pair of character iterators whose `value_type` is an integral type
+    with a size of 1, 2, or 4 bytes (interpreted respectively as UTF-8, UTF-16, and UTF-32)
 
 `SAX`
-:   Description
+:   a class fulfilling the SAX event listener interface; see [`json_sax`](../json_sax/index.md)
 
 ## Parameters
 
 `i` (in)
-:   Input to parse from.
+:   Input to parse from
 
 `sax` (in)
-:   SAX event listener
+:   SAX event listener (must not be null)
 
 `format` (in)
 :    the format to parse (JSON, CBOR, MessagePack, or UBJSON) (optional, `input_format_t::json` by default), see
@@ -65,6 +68,10 @@ The SAX event lister must follow the interface of [`json_sax`](../json_sax/index
 :   whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
     (`#!cpp false`); (optional, `#!cpp false` by default)
 
+`ignore_trailing_commas` (in)
+:   whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
+    (`#!cpp false`); (optional, `#!cpp false` by default)
+
 `first` (in)
 :   iterator to the start of a character range
 
@@ -77,6 +84,13 @@ return value of the last processed SAX event
 
 ## Exception safety
 
+Strong guarantee: if an exception is thrown, there are no changes in the JSON value.
+
+## Exceptions
+
+- Throws [`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101) in case of an unexpected token, or
+  empty input like a null `FILE*` or `char*` pointer.
+
 ## Complexity
 
 Linear in the length of the input. The parser is a predictive LL(1) parser. The complexity can be higher if the SAX
@@ -103,10 +117,16 @@ A UTF-8 byte order mark is silently ignored.
     --8<-- "examples/sax_parse.output"
     ```
 
+## See also
+
+- [parse](parse.md) - deserialize from a compatible input
+- [accept](accept.md) - check if the input is valid JSON
+
 ## Version history
 
 - Added in version 3.2.0.
 - Ignoring comments via `ignore_comments` added in version 3.9.0.
+- Added `ignore_trailing_commas` in version 3.12.x.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json/std_formatter.md

@@ -0,0 +1,56 @@
+# <small>std::</small>formatter<nlohmann::basic_json\>
+
+```cpp
+namespace std {
+    template <>
+    struct formatter<nlohmann::basic_json, char>;
+}
+```
+
+Specialization to make JSON values formattable with [`std::format`](https://en.cppreference.com/w/cpp/utility/format/format)
+(and the other members of C++20's `<format>` header, such as `std::format_to`).
+
+A subset of the [standard format spec grammar](https://en.cppreference.com/w/cpp/utility/format/spec) is
+supported, repurposed for JSON pretty-printing; any other spec component (sign, the `0` flag, precision,
+`L`, a dynamic width such as `#!cpp "{:{}}"`, or a trailing type character) throws
+[`std::format_error`](https://en.cppreference.com/w/cpp/utility/format/format_error):
+
+- `#!cpp "{}"` serializes the value the same way as [`dump()`](dump.md) (compact, no whitespace).
+- `#!cpp "{:#}"` ("alternate form") serializes the value the same way as `#!cpp dump(4)` (pretty-printed
+  with an indent of 4).
+- A width, with or without `#!cpp "#"` (e.g. `#!cpp "{:2}"` or `#!cpp "{:#2}"`), serializes the value the
+  same way as `#!cpp dump(width)` — a width on its own implies pretty-printing, since an indent size has
+  no meaning for compact output.
+- `fill-and-align` (e.g. `#!cpp "{:.>#}"` or `#!cpp "{:.>3}"`) picks a custom indent character, the same
+  way as `#!cpp dump(indent, indent_char)`. The alignment direction itself (`#!cpp '<'`, `#!cpp '>'`,
+  `#!cpp '^'`) has no separate meaning for JSON values — only the fill character before it is used, and
+  any of the three directions is accepted.
+
+This specialization is only available for `#!cpp char`-based JSON values and only if the standard library
+provides `<format>`, controlled by the [`JSON_HAS_STD_FORMAT`](../macros/json_has_std_format.md) macro.
+
+## Examples
+
+??? example
+
+    The example shows how to format JSON values with `std::format`.
+
+    ```cpp
+    --8<-- "examples/std_formatter.c++20.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/std_formatter.c++20.output"
+    ```
+
+## See also
+
+- [dump](dump.md) - serialization
+- [operator<<(std::ostream&)](../operator_ltlt.md) - serialize to stream
+- [format_as](format_as.md) - customization point used by `fmt::format` (fmtlib)
+
+## Version history
+
+- Added in version 3.12.x.

docs/mkdocs/docs/api/basic_json/std_swap.md

@@ -16,6 +16,14 @@ Exchanges the values of two JSON objects.
 `j2` (in, out)
 :   value to be replaced by `j1`
 
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
 ## Possible implementation
 
 ```cpp

docs/mkdocs/docs/api/basic_json/string_t.md

@@ -9,7 +9,7 @@ The type used to store JSON strings.
 [RFC 8259](https://tools.ietf.org/html/rfc8259) describes JSON strings as follows:
 > A string is a sequence of zero or more Unicode characters.
 
-To store objects in C++, a type is defined by the template parameter described below. Unicode values are split by the
+To store strings in C++, a type is defined by the template parameter described below. Unicode values are split by the
 JSON class into byte-sized characters during deserialization.
 
 ## Template parameters

docs/mkdocs/docs/api/basic_json/swap.md

@@ -2,10 +2,20 @@
 
 ```cpp
 // (1)
-void swap(reference other) noexcept;
+void swap(reference other) noexcept (
+    std::is_nothrow_move_constructible<value_t>::value &&
+    std::is_nothrow_move_assignable<value_t>::value &&
+    std::is_nothrow_move_constructible<json_value>::value &&
+    std::is_nothrow_move_assignable<json_value>::value
+);
 
 // (2)
-void swap(reference left, reference right) noexcept;
+friend void swap(reference left, reference right) noexcept (
+    std::is_nothrow_move_constructible<value_t>::value &&
+    std::is_nothrow_move_assignable<value_t>::value &&
+    std::is_nothrow_move_constructible<json_value>::value &&
+    std::is_nothrow_move_assignable<json_value>::value
+);
 
 // (3)
 void swap(array_t& other);
@@ -56,15 +66,15 @@ void swap(typename binary_t::container_type& other);
 1. No-throw guarantee: this function never throws exceptions.
 2. No-throw guarantee: this function never throws exceptions.
 3. Throws [`type_error.310`](../../home/exceptions.md#jsonexceptiontype_error310) if called on JSON values other than
-   arrays; example: `"cannot use swap() with boolean"`
+   arrays; example: `"cannot use swap(array_t&) with boolean"`
 4. Throws [`type_error.310`](../../home/exceptions.md#jsonexceptiontype_error310) if called on JSON values other than
-   objects; example: `"cannot use swap() with boolean"`
+   objects; example: `"cannot use swap(object_t&) with boolean"`
 5. Throws [`type_error.310`](../../home/exceptions.md#jsonexceptiontype_error310) if called on JSON values other than
-   strings; example: `"cannot use swap() with boolean"`
+   strings; example: `"cannot use swap(string_t&) with boolean"`
 6. Throws [`type_error.310`](../../home/exceptions.md#jsonexceptiontype_error310) if called on JSON values other than
-   binaries; example: `"cannot use swap() with boolean"`
+   binaries; example: `"cannot use swap(binary_t&) with boolean"`
 7. Throws [`type_error.310`](../../home/exceptions.md#jsonexceptiontype_error310) if called on JSON values other than
-   binaries; example: `"cannot use swap() with boolean"`
+   binaries; example: `"cannot use swap(binary_t::container_type&) with boolean"`
 
 ## Complexity
 
@@ -128,7 +138,7 @@ Constant.
     --8<-- "examples/swap__string_t.output"
     ```
 
-??? example "Example: Swap string (6)"
+??? example "Example: Swap binary (6)"
 
     The example below shows how binary values can be swapped with `swap()`.
     
@@ -145,6 +155,8 @@ Constant.
 ## See also
 
 - [std::swap<basic_json\>](std_swap.md)
+- [operator=](operator=.md) copy assignment
+- [basic_json](basic_json.md) create a JSON value
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json/to_bjdata.md

@@ -72,6 +72,14 @@ Linear in the size of the JSON value `j`.
     --8<-- "examples/to_bjdata.output"
     ```
 
+## See also
+
+- [from_bjdata](from_bjdata.md) create a JSON value from an input in BJData format
+- [to_cbor](to_cbor.md) create a CBOR serialization of a JSON value
+- [to_msgpack](to_msgpack.md) create a MessagePack serialization of a JSON value
+- [to_bson](to_bson.md) create a BSON serialization of a JSON value
+- [to_ubjson](to_ubjson.md) create a UBJSON serialization of a JSON value
+
 ## Version history
 
 - Added in version 3.11.0.

docs/mkdocs/docs/api/basic_json/to_bson.md

@@ -34,6 +34,13 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 
 Strong guarantee: if an exception is thrown, there are no changes in the JSON value.
 
+## Exceptions
+
+- Throws [`type_error.317`](../../home/exceptions.md#jsonexceptiontype_error317) if the top-level type of the JSON value
+  is not an object; example: `"to serialize to BSON, top-level type must be object, but is string"`
+- Throws [`out_of_range.409`](../../home/exceptions.md#jsonexceptionout_of_range409) if a key in the JSON object contains
+  a null byte (code point U+0000); example: `"BSON key cannot contain code point U+0000 (at byte 2)"`
+
 ## Complexity
 
 Linear in the size of the JSON value `j`.
@@ -54,6 +61,14 @@ Linear in the size of the JSON value `j`.
     --8<-- "examples/to_bson.output"
     ```
 
+## See also
+
+- [from_bson](from_bson.md) create a JSON value from an input in BSON format
+- [to_cbor](to_cbor.md) create a CBOR serialization of a JSON value
+- [to_msgpack](to_msgpack.md) create a MessagePack serialization of a JSON value
+- [to_ubjson](to_ubjson.md) create a UBJSON serialization of a JSON value
+- [to_bjdata](to_bjdata.md) create a BJData serialization of a JSON value
+
 ## Version history
 
 - Added in version 3.4.0.

docs/mkdocs/docs/api/basic_json/to_cbor.md

@@ -55,6 +55,14 @@ Linear in the size of the JSON value `j`.
     --8<-- "examples/to_cbor.output"
     ```
 
+## See also
+
+- [from_cbor](from_cbor.md) create a JSON value from an input in CBOR format
+- [to_msgpack](to_msgpack.md) create a MessagePack serialization of a JSON value
+- [to_bson](to_bson.md) create a BSON serialization of a JSON value
+- [to_ubjson](to_ubjson.md) create a UBJSON serialization of a JSON value
+- [to_bjdata](to_bjdata.md) create a BJData serialization of a JSON value
+
 ## Version history
 
 - Added in version 2.0.9.

docs/mkdocs/docs/api/basic_json/to_msgpack.md

@@ -54,6 +54,14 @@ Linear in the size of the JSON value `j`.
     --8<-- "examples/to_msgpack.output"
     ```
 
+## See also
+
+- [from_msgpack](from_msgpack.md) create a JSON value from an input in MessagePack format
+- [to_cbor](to_cbor.md) create a CBOR serialization of a JSON value
+- [to_bson](to_bson.md) create a BSON serialization of a JSON value
+- [to_ubjson](to_ubjson.md) create a UBJSON serialization of a JSON value
+- [to_bjdata](to_bjdata.md) create a BJData serialization of a JSON value
+
 ## Version history
 
 - Added in version 2.0.9.