Merge branch 'release/3.8.0' into develop

Improve parse_ubjson_fuzzer

.circleci/config.yml

@@ -0,0 +1,48 @@
+version: 2
+jobs:
+  build_stable:
+    docker:
+      - image: debian:stretch
+
+    steps:
+      - checkout
+
+      - run:
+          name: Install required tools
+          command: 'apt-get update && apt-get install -y gcc g++ git cmake'
+      - run:
+          name: Run CMake
+          command: 'mkdir build ; cd build ; cmake .. -DJSON_BuildTests=On'
+      - run:
+          name: Compile
+          command: 'cmake --build build'
+      - run:
+          name: Execute test suite
+          command: 'cd build ; ctest --output-on-failure -j 2'
+
+  build_bleeding_edge:
+    docker:
+      - image: archlinux
+
+    steps:
+      - checkout
+
+      - run:
+          name: Install required tools
+          command: 'pacman -Sy --noconfirm base base-devel gcc git cmake'
+      - run:
+          name: Run CMake
+          command: 'mkdir build ; cd build ; cmake .. -DJSON_BuildTests=On'
+      - run:
+          name: Compile
+          command: 'cmake --build build'
+      - run:
+          name: Execute test suite
+          command: 'cd build ; ctest --output-on-failure -j 2'
+
+workflows:
+  version: 2
+  build_and_test_all:
+    jobs:
+      - build_stable
+      - build_bleeding_edge

.clang-tidy

@@ -4,14 +4,17 @@ Checks: '-*,
          clang-analyzer-*,
          google-*,
          -google-runtime-references,
+         -google-explicit-constructor,
          hicpp-*,
          -hicpp-no-array-decay,
          -hicpp-uppercase-literal-suffix,
+         -hicpp-explicit-conversions,
          misc-*,
          -misc-non-private-member-variables-in-classes,
          llvm-*,
          -llvm-header-guard,
          modernize-*,
+         -modernize-use-trailing-return-type,
          performance-*,
          portability-*,
          readability-*,

.github/CODEOWNERS

@@ -0,0 +1,6 @@
+# JSON for Modern C++ has been originally written by Niels Lohmann.
+# Since 2013 over 140 contributors have helped to improve the library.
+# This CODEOWNERS file is only to make sure that @nlohmann is requested
+# for a code review in case of a pull request.
+
+* @nlohmann

.github/CONTRIBUTING.md

@@ -4,7 +4,7 @@
 
 This project started as a little excuse to exercise some of the cool new C++11 features. Over time, people actually started to use the JSON library (yey!) and started to help improve it by proposing features, finding bugs, or even fixing my mistakes. I am really [thankful](https://github.com/nlohmann/json/blob/master/README.md#thanks) for this and try to keep track of all the helpers.
 
-To make it as easy as possible for you to contribute and for me to keep an overview, here are a few guidelines which should help us avoid all kinds of unnecessary work or disappointment. And of course, this document is subject to discussion, so please [create an issue](https://github.com/nlohmann/json/issues/new) or a pull request if you find a way to improve it!
+To make it as easy as possible for you to contribute and for me to keep an overview, here are a few guidelines which should help us avoid all kinds of unnecessary work or disappointment. And of course, this document is subject to discussion, so please [create an issue](https://github.com/nlohmann/json/issues/new/choose) or a pull request if you find a way to improve it!
 
 ## Private reports
 
@@ -12,7 +12,7 @@ Usually, all issues are tracked publicly on [GitHub](https://github.com/nlohmann
 
 ## Prerequisites
 
-Please [create an issue](https://github.com/nlohmann/json/issues/new), assuming one does not already exist, and describe your concern. Note you need a [GitHub account](https://github.com/signup/free) for this.
+Please [create an issue](https://github.com/nlohmann/json/issues/new/choose), assuming one does not already exist, and describe your concern. Note you need a [GitHub account](https://github.com/signup/free) for this.
 
 ## Describe your issue
 
@@ -22,7 +22,7 @@ Clearly describe the issue:
 - If you propose a change or addition, try to give an **example** how 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.
 
-Please stick to the [issue template](https://github.com/nlohmann/json/blob/develop/.github/ISSUE_TEMPLATE.md) if possible.
+Please stick to the provided issue templates ([bug report](https://github.com/nlohmann/json/blob/develop/.github/ISSUE_TEMPLATE/Bug_report.md), [feature request](https://github.com/nlohmann/json/blob/develop/.github/ISSUE_TEMPLATE/Feature_request.md), or [question](https://github.com/nlohmann/json/blob/develop/.github/ISSUE_TEMPLATE/question.md)) if possible.
 
 ## Files to change
 
@@ -32,7 +32,7 @@ To make changes, you need to edit the following files:
 
 1. [`include/nlohmann/*`](https://github.com/nlohmann/json/tree/develop/include/nlohmann) - These files are the sources of the library. Before testing or creating a pull request, execute `make amalgamate` to regenerate `single_include/nlohmann/json.hpp`.
 
-2. [`test/src/unit-*.cpp`](https://github.com/nlohmann/json/tree/develop/test/src) - These files contain the [Catch](https://github.com/philsquared/Catch) unit tests which currently cover [100 %](https://coveralls.io/github/nlohmann/json) of the library's code.
+2. [`test/src/unit-*.cpp`](https://github.com/nlohmann/json/tree/develop/test/src) - These files contain the [doctest](https://github.com/onqtam/doctest) unit tests which currently cover [100 %](https://coveralls.io/github/nlohmann/json) of the library's code.
 
    If you add or change a feature, please also add a unit test to this file. The unit tests can be compiled and executed with
 
@@ -56,7 +56,7 @@ To make changes, you need to edit the following files:
 
 - The C++11 support varies between different **compilers** and versions. Please note the [list of supported compilers](https://github.com/nlohmann/json/blob/master/README.md#supported-compilers). Some compilers like GCC 4.7 (and earlier), Clang 3.3 (and earlier), or Microsoft Visual Studio 13.0 and earlier are known not to work due to missing or incomplete C++11 support. Please refrain from proposing changes that work around these compiler's limitations with `#ifdef`s or other means.
 - Specifically, I am aware of compilation problems with **Microsoft Visual Studio** (there even is an [issue label](https://github.com/nlohmann/json/issues?utf8=✓&q=label%3A%22visual+studio%22+) for these kind of bugs). I understand that even in 2016, complete C++11 support isn't there yet. But please also understand that I do not want to drop features or uglify the code just to make Microsoft's sub-standard compiler happy. The past has shown that there are ways to express the functionality such that the code compiles with the most recent MSVC - unfortunately, this is not the main objective of the project.
-- Please refrain from proposing changes that would **break [JSON](http://json.org) conformance**. If you propose a conformant extension of JSON to be supported by the library, please motivate this extension.
+- Please refrain from proposing changes that would **break [JSON](https://json.org) conformance**. If you propose a conformant extension of JSON to be supported by the library, please motivate this extension.
   - We shall not extend the library to **support comments**. There is quite some [controversy](https://www.reddit.com/r/programming/comments/4v6chu/why_json_doesnt_support_comments_douglas_crockford/) around this topic, and there were quite some [issues](https://github.com/nlohmann/json/issues/376) on this. We believe that JSON is fine without comments.
   - We do not preserve the **insertion order of object elements**. The [JSON standard](https://tools.ietf.org/html/rfc7159.html) defines objects as "an unordered collection of zero or more name/value pairs". To this end, this library does not preserve insertion order of name/value pairs. (In fact, keys will be traversed in alphabetical order as `std::map` with `std::less` is used by default.) Note this behavior conforms to the standard, and we shall not change it to any other order. If you do want to preserve the insertion order, you can specialize the object type with containers like [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) or [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map).
 
@@ -66,6 +66,6 @@ To make changes, you need to edit the following files:
 
 The following areas really need contribution:
 
-- Extending the **continuous integration** toward more exotic compilers such as Android NDK, Intel's Compiler, or the bleeding-edge versions of GCC or Clang.
+- 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 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.
 - Extending and updating existing **benchmarks** to include (the most recent version of) this library. Though efficiency is not everything, speed and memory consumption are very important characteristics for C++ developers, so having proper comparisons would be interesting.

.github/FUNDING.yml

@@ -1 +1,2 @@
+github: nlohmann
 custom: http://paypal.me/nlohmann

.github/ISSUE_TEMPLATE/Bug_report.md

@@ -7,16 +7,51 @@ assignees: ''
 
 ---
 
-- What is the issue you have?
+<!-- Provide a concise summary of the issue in the title above. -->
 
-- Please describe the steps to reproduce the issue. Can you provide a small but working code example?
+#### What is the issue you have?
 
-- What is the expected behavior?
+<!-- Provide a detailed introduction to the issue itself, and why you consider it to be a bug. -->
+<!-- If possible, be specific and add stack traces, error messages, etc. Avoid vague terms like "crash" or "doesn't work". -->
 
-- And what is the actual behavior instead?
+#### Please describe the steps to reproduce the issue.
 
-- Which compiler and operating system are you using? Is it a [supported compiler](https://github.com/nlohmann/json#supported-compilers)?
+<!-- Provide a link to a live example, or an unambiguous set of steps to -->
+<!-- reproduce this bug. Include code to reproduce, if relevant -->
 
-- Did you use a released version of the library or the version from the `develop` branch?
+1.
+2.
+3.
 
-- If you experience a compilation error: can you [compile and run the unit tests](https://github.com/nlohmann/json#execute-unit-tests)?
+#### Can you provide a small but working code example?
+
+<!-- Please understand that we cannot analyze and debug large code bases. -->
+
+#### What is the expected behavior?
+
+<!-- Tell us what should happen -->
+
+#### And what is the actual behavior instead?
+
+<!-- Tell us what happens instead. -->
+
+#### Which compiler and operating system are you using?
+
+<!-- Include as many relevant details about the environment you experienced the bug in. -->
+<!-- Make sure you use a supported compiler, see https://github.com/nlohmann/json#supported-compilers. -->
+
+- Compiler: ___
+- Operating system: ___
+
+#### Which version of the library did you use?
+
+<!-- Please add an `x` to the respective line. -->
+
+- [ ] latest release version 3.7.3
+- [ ] other release - please state the version: ___
+- [ ] the `develop` branch
+
+#### If you experience a compilation error: can you [compile and run the unit tests](https://github.com/nlohmann/json#execute-unit-tests)?
+
+- [ ] yes
+- [ ] no - please copy/paste the error message below

.github/ISSUE_TEMPLATE/Feature_request.md

@@ -7,6 +7,10 @@ assignees: ''
 
 ---
 
-- Describe the feature in as much detail as possible.
+#### Which feature do you want to see in the library?
 
-- Include sample usage where appropriate.
+<!-- Describe the feature in as much detail as possible. -->
+
+#### How would the feature be usable for other users?
+
+<!-- Include sample usage where appropriate. -->

.github/ISSUE_TEMPLATE/question.md

@@ -7,10 +7,34 @@ assignees: ''
 
 ---
 
-- Describe what you want to achieve.
+<!-- Provide a concise summary of the issue in the title above. -->
 
-- Describe what you tried.
+#### What do you want to achieve?
 
-- Describe which system (OS, compiler) you are using.
+<!-- Please describe the feature as detailed as possible. -->
 
-- Describe which version of the library you are using (release version, develop branch).
+#### What have you tried?
+
+<!-- There are thousands of issues to search: https://github.com/nlohmann/json/issues?q=is%3Aissue+ -->
+<!-- There is a full documentation of the API: https://nlohmann.github.io/json/ -->
+<!-- There is a detailed README file: https://github.com/nlohmann/json/blob/develop/README.md -->
+
+#### Can you provide a small code example?
+
+<!-- Please understand that we cannot analyze and debug large code bases. -->
+
+#### Which compiler and operating system are you using?
+
+<!-- Include as many relevant details about the environment you experienced the bug in. -->
+<!-- Make sure you use a supported compiler, see https://github.com/nlohmann/json#supported-compilers. -->
+
+- Compiler: ___
+- Operating system: ___
+
+#### Which version of the library did you use?
+
+<!-- Please add an `x` to the respective line. -->
+
+- [ ] latest release version 3.7.3
+- [ ] other release - please state the version: ___
+- [ ] the `develop` branch

.github/PULL_REQUEST_TEMPLATE.md

@@ -15,5 +15,5 @@ Read the [Contribution Guidelines](https://github.com/nlohmann/json/blob/develop
 
 - The C++11 support varies between different **compilers** and versions. Please note the [list of supported compilers](https://github.com/nlohmann/json/blob/master/README.md#supported-compilers). Some compilers like GCC 4.7 (and earlier), Clang 3.3 (and earlier), or Microsoft Visual Studio 13.0 and earlier are known not to work due to missing or incomplete C++11 support. Please refrain from proposing changes that work around these compiler's limitations with `#ifdef`s or other means.
 - Specifically, I am aware of compilation problems with **Microsoft Visual Studio** (there even is an [issue label](https://github.com/nlohmann/json/issues?utf8=✓&q=label%3A%22visual+studio%22+) for these kind of bugs). I understand that even in 2016, complete C++11 support isn't there yet. But please also understand that I do not want to drop features or uglify the code just to make Microsoft's sub-standard compiler happy. The past has shown that there are ways to express the functionality such that the code compiles with the most recent MSVC - unfortunately, this is not the main objective of the project.
-- Please refrain from proposing changes that would **break [JSON](http://json.org) conformance**. If you propose a conformant extension of JSON to be supported by the library, please motivate this extension.
+- Please refrain from proposing changes that would **break [JSON](https://json.org) conformance**. If you propose a conformant extension of JSON to be supported by the library, please motivate this extension.
 - Please do not open pull requests that address **multiple issues**.

.github/SECURITY.md

@@ -0,0 +1,5 @@
+# Security Policy
+
+## Reporting a Vulnerability
+
+Usually, all issues are tracked publicly on [GitHub](https://github.com/nlohmann/json/issues). If you want to make a private report (e.g., for a vulnerability or to attach an example that is not meant to be published), please send an email to <mail@nlohmann.me>. You can use [this key](https://keybase.io/nlohmann/pgp_keys.asc?fingerprint=797167ae41c0a6d9232e48457f3cea63ae251b69) for encryption.

.github/workflows/macos.yml

@@ -0,0 +1,17 @@
+name: macOS
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: cmake
+      run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On
+    - name: build
+      run: cmake --build build --parallel 10
+    - name: test
+      run: cd build ; ctest -j 10 --output-on-failure

.github/workflows/ubuntu.yml

@@ -0,0 +1,17 @@
+name: Ubuntu
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: cmake
+      run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On
+    - name: build
+      run: cmake --build build --parallel 10
+    - name: test
+      run: cd build ; ctest -j 10 --output-on-failure

.github/workflows/windows.yml

@@ -0,0 +1,17 @@
+name: Windows
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: cmake
+      run: cmake -S . -B build -G "Visual Studio 16 2019" -D CMAKE_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

.gitignore

@@ -18,8 +18,17 @@ me.nlohmann.json.docset
 
 benchmarks/files/numbers/*.json
 
+.wsjcpp-logs/*
+.wsjcpp/*
+
 .idea
 cmake-build-debug
 
 test/test-*
 /.vs
+
+doc/mkdocs/venv/
+doc/mkdocs/docs/images
+doc/mkdocs/docs/examples
+doc/mkdocs/site
+doc/mkdocs/docs/__pycache__/

.travis.yml

@@ -43,12 +43,15 @@ matrix:
   - os: linux
     compiler: clang
     env:
-      - COMPILER=clang++-5.0
+      - COMPILER=clang++-7
       - CMAKE_OPTIONS=-DJSON_Sanitizer=ON
+      - UBSAN_OPTIONS=print_stacktrace=1,suppressions=$(pwd)/test/src/UBSAN.supp
     addons:
       apt:
-        sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-trusty-5.0']
-        packages: ['g++-6', 'clang-5.0', 'ninja-build']
+        sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-trusty-7']
+        packages: ['g++-6', 'clang-7', 'ninja-build']
+    before_script:
+      - export PATH=$PATH:/usr/lib/llvm-7/bin
 
   # cppcheck
   - os: linux
@@ -92,16 +95,17 @@ matrix:
 
   - os: linux
     compiler: gcc
+    dist: bionic
     addons:
       apt:
         sources: ['ubuntu-toolchain-r-test']
-        packages: ['g++-4.9', 'ninja-build']
+        packages: ['g++-7', 'ninja-build']
     before_script:
       - pip install --user cpp-coveralls
     after_success:
-      - coveralls --build-root test --include include/nlohmann --gcov 'gcov-4.9' --gcov-options '\-lp'
+      - coveralls --build-root test --include include/nlohmann --gcov 'gcov-7' --gcov-options '\-lp'
     env:
-      - COMPILER=g++-4.9
+      - COMPILER=g++-7
       - CMAKE_OPTIONS=-DJSON_Coverage=ON
       - MULTIPLE_HEADERS=ON
 
@@ -128,18 +132,6 @@ matrix:
 
   # OSX / Clang
 
-  - os: osx
-    osx_image: xcode8.3
-
-  - os: osx
-    osx_image: xcode9
-
-  - os: osx
-    osx_image: xcode9.1
-
-  - os: osx
-    osx_image: xcode9.2
-
   - os: osx
     osx_image: xcode9.3
 
@@ -152,11 +144,17 @@ matrix:
   - os: osx
     osx_image: xcode10.1
 
+  - os: osx
+    osx_image: xcode10.2
+
+  - os: osx
+    osx_image: xcode11.2
+
   # Linux / GCC
 
   - os: linux
     compiler: gcc
-    env: compiler=g++-4.8
+    env: COMPILER=g++-4.8
     addons:
       apt:
         sources: ['ubuntu-toolchain-r-test']
@@ -164,7 +162,7 @@ matrix:
 
   - os: linux
     compiler: gcc
-    env: compiler=g++-4.9
+    env: COMPILER=g++-4.9
     addons:
       apt:
         sources: ['ubuntu-toolchain-r-test']
@@ -204,13 +202,21 @@ matrix:
 
   - os: linux
     compiler: gcc
-    env:
-      - COMPILER=g++-8
-      - CXXFLAGS=-std=c++17
+    env: COMPILER=g++-9
     addons:
       apt:
         sources: ['ubuntu-toolchain-r-test']
-        packages: ['g++-8', 'ninja-build']
+        packages: ['g++-9', 'ninja-build']
+
+  - os: linux
+    compiler: gcc
+    env:
+      - COMPILER=g++-9
+      - CXXFLAGS=-std=c++2a
+    addons:
+      apt:
+        sources: ['ubuntu-toolchain-r-test']
+        packages: ['g++-9', 'ninja-build']
 
   # Linux / Clang
 
@@ -315,14 +321,10 @@ script:
   # by default, use the single-header version
   - if [[ "${MULTIPLE_HEADERS}" == "" ]]; then export MULTIPLE_HEADERS=OFF; fi
 
-  # show OS/compiler version
-  - uname -a
-  - $CXX --version
-
   # compile and execute unit tests
   - mkdir -p build && cd build
-  - cmake .. ${CMAKE_OPTIONS} -DJSON_MultipleHeaders=${MULTIPLE_HEADERS} -GNinja && cmake --build . --config Release
-  - ctest -C Release -V -j
+  - cmake .. ${CMAKE_OPTIONS} -DJSON_MultipleHeaders=${MULTIPLE_HEADERS} -DJSON_BuildTests=On -GNinja && cmake --build . --config Release
+  - ctest -C Release --timeout 2700 -V -j
   - cd ..
 
   # check if homebrew works (only checks develop branch)   

CMakeLists.txt

@@ -4,7 +4,7 @@ cmake_minimum_required(VERSION 3.1)
 ## PROJECT
 ## name and version
 ##
-project(nlohmann_json VERSION 3.6.1 LANGUAGES CXX)
+project(nlohmann_json VERSION 3.8.0 LANGUAGES CXX)
 
 ##
 ## INCLUDE
@@ -22,10 +22,11 @@ option(JSON_MultipleHeaders "Use non-amalgamated version of the library." OFF)
 ##
 ## CONFIGURATION
 ##
+include(GNUInstallDirs)
+
 set(NLOHMANN_JSON_TARGET_NAME               ${PROJECT_NAME})
-set(NLOHMANN_JSON_CONFIG_INSTALL_DIR        "lib/cmake/${PROJECT_NAME}"
-  CACHE INTERNAL "")
-set(NLOHMANN_JSON_INCLUDE_INSTALL_DIR       "include")
+set(NLOHMANN_JSON_CONFIG_INSTALL_DIR        "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}" CACHE INTERNAL "")
+set(NLOHMANN_JSON_INCLUDE_INSTALL_DIR       "${CMAKE_INSTALL_INCLUDEDIR}")
 set(NLOHMANN_JSON_TARGETS_EXPORT_NAME       "${PROJECT_NAME}Targets")
 set(NLOHMANN_JSON_CMAKE_CONFIG_TEMPLATE     "cmake/config.cmake.in")
 set(NLOHMANN_JSON_CMAKE_CONFIG_DIR          "${CMAKE_CURRENT_BINARY_DIR}")
@@ -47,7 +48,7 @@ endif()
 ##
 add_library(${NLOHMANN_JSON_TARGET_NAME} INTERFACE)
 add_library(${PROJECT_NAME}::${NLOHMANN_JSON_TARGET_NAME} ALIAS ${NLOHMANN_JSON_TARGET_NAME})
-if (${CMAKE_VERSION} VERSION_LESS "3.8.0") 
+if (${CMAKE_VERSION} VERSION_LESS "3.8.0")
     target_compile_features(${NLOHMANN_JSON_TARGET_NAME} INTERFACE cxx_range_for)
 else()
     target_compile_features(${NLOHMANN_JSON_TARGET_NAME} INTERFACE cxx_std_11)
@@ -88,8 +89,13 @@ endif()
 ## install header files, generate and install cmake config files for find_package()
 ##
 include(CMakePackageConfigHelpers)
-write_basic_package_version_file(
-    ${NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE} COMPATIBILITY SameMajorVersion
+# use a custom package version config file instead of
+# write_basic_package_version_file to ensure that it's architecture-independent
+# https://github.com/nlohmann/json/issues/1697
+configure_file(
+    "cmake/nlohmann_jsonConfigVersion.cmake.in"
+    ${NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE}
+    @ONLY
 )
 configure_file(
     ${NLOHMANN_JSON_CMAKE_CONFIG_TEMPLATE}
@@ -111,7 +117,7 @@ if(JSON_Install)
             FILES ${NLOHMANN_NATVIS_FILE}
             DESTINATION .
     )
-    endif()
+endif()
     export(
         TARGETS ${NLOHMANN_JSON_TARGET_NAME}
         NAMESPACE ${PROJECT_NAME}::

LICENSE.MIT

@@ -1,6 +1,6 @@
 MIT License 
 
-Copyright (c) 2013-2019 Niels Lohmann
+Copyright (c) 2013-2020 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

Makefile

@@ -1,51 +1,37 @@
-.PHONY: pretty clean ChangeLog.md
+.PHONY: pretty clean ChangeLog.md release
 
-SRCS = include/nlohmann/json.hpp \
-       include/nlohmann/json_fwd.hpp \
-       include/nlohmann/adl_serializer.hpp \
-       include/nlohmann/detail/conversions/from_json.hpp \
-       include/nlohmann/detail/conversions/to_chars.hpp \
-       include/nlohmann/detail/conversions/to_json.hpp \
-       include/nlohmann/detail/exceptions.hpp \
-       include/nlohmann/detail/input/binary_reader.hpp \
-       include/nlohmann/detail/input/input_adapters.hpp \
-       include/nlohmann/detail/input/json_sax.hpp \
-       include/nlohmann/detail/input/lexer.hpp \
-       include/nlohmann/detail/input/parser.hpp \
-       include/nlohmann/detail/input/position_t.hpp \
-       include/nlohmann/detail/iterators/internal_iterator.hpp \
-       include/nlohmann/detail/iterators/iter_impl.hpp \
-       include/nlohmann/detail/iterators/iteration_proxy.hpp \
-       include/nlohmann/detail/iterators/json_reverse_iterator.hpp \
-       include/nlohmann/detail/iterators/primitive_iterator.hpp \
-       include/nlohmann/detail/json_pointer.hpp \
-       include/nlohmann/detail/json_ref.hpp \
-       include/nlohmann/detail/macro_scope.hpp \
-       include/nlohmann/detail/macro_unscope.hpp \
-       include/nlohmann/detail/meta/cpp_future.hpp \
-       include/nlohmann/detail/meta/detected.hpp \
-       include/nlohmann/detail/meta/type_traits.hpp \
-       include/nlohmann/detail/meta/void_t.hpp \
-       include/nlohmann/detail/output/binary_writer.hpp \
-       include/nlohmann/detail/output/output_adapters.hpp \
-       include/nlohmann/detail/output/serializer.hpp \
-       include/nlohmann/detail/value_t.hpp
-
-UNAME = $(shell uname)
-CXX=clang++
-
-AMALGAMATED_FILE=single_include/nlohmann/json.hpp
+##########################################################################
+# configuration
+##########################################################################
 
 # directory to recent compiler binaries
 COMPILER_DIR=/Users/niels/Documents/projects/compilers/local/bin
 
+# find GNU sed to use `-i` parameter
+SED:=$(shell command -v gsed || which sed)
+
+
+##########################################################################
+# source files
+##########################################################################
+
+# the list of sources in the include folder
+SRCS=$(shell find include -type f | sort)
+
+# the single header (amalgamated from the source files)
+AMALGAMATED_FILE=single_include/nlohmann/json.hpp
+
+
+##########################################################################
+# documentation of the Makefile's targets
+##########################################################################
+
 # main target
 all:
 	@echo "amalgamate - amalgamate file single_include/nlohmann/json.hpp from the include/nlohmann sources"
 	@echo "ChangeLog.md - generate ChangeLog file"
 	@echo "check - compile and execute test suite"
 	@echo "check-amalgamation - check whether sources have been amalgamated"
-	@echo "check-fast - compile and execute test suite (skip long-running tests)"
 	@echo "clean - remove built files"
 	@echo "coverage - create coverage information with lcov"
 	@echo "cppcheck - analyze code with cppcheck"
@@ -64,6 +50,7 @@ all:
 	@echo "pretty - beautify code with Artistic Style"
 	@echo "run_benchmarks - build and run benchmarks"
 
+
 ##########################################################################
 # unit tests
 ##########################################################################
@@ -76,31 +63,20 @@ json_unit:
 check:
 	$(MAKE) check -C test
 
-check-fast:
-	$(MAKE) check -C test TEST_PATTERN=""
-
-# clean up
-clean:
-	rm -fr json_unit json_benchmarks fuzz fuzz-testing *.dSYM test/*.dSYM
-	rm -fr benchmarks/files/numbers/*.json
-	rm -fr build_coverage build_benchmarks
-	$(MAKE) clean -Cdoc
-	$(MAKE) clean -Ctest
-
 
 ##########################################################################
 # coverage
 ##########################################################################
 
 coverage:
+	rm -fr build_coverage
 	mkdir build_coverage
-	cd build_coverage ; CXX=g++-7 cmake .. -GNinja -DJSON_Coverage=ON -DJSON_MultipleHeaders=ON
+	cd build_coverage ; cmake .. -GNinja -DCMAKE_BUILD_TYPE=Debug -DJSON_Coverage=ON -DJSON_MultipleHeaders=ON
 	cd build_coverage ; ninja
-	cd build_coverage ; ctest -E '.*_default' -j10
+	cd build_coverage ; ctest -j10
 	cd build_coverage ; ninja lcov_html
 	open build_coverage/test/html/index.html
 
-
 ##########################################################################
 # documentation tests
 ##########################################################################
@@ -115,266 +91,306 @@ doctest:
 ##########################################################################
 
 # calling Clang with all warnings, except:
-# -Wno-documentation-unknown-command: code uses user-defined commands like @complexity
-# -Wno-exit-time-destructors: warning in Catch code
-# -Wno-keyword-macro: unit-tests use "#define private public"
-# -Wno-deprecated-declarations: the library deprecated some functions
-# -Wno-weak-vtables: exception class is defined inline, but has virtual method
-# -Wno-range-loop-analysis: items tests "for(const auto i...)"
-# -Wno-float-equal: not all comparisons in the tests can be replaced by Approx
-# -Wno-switch-enum -Wno-covered-switch-default: pedantic/contradicting warnings about switches
 # -Wno-c++2a-compat: u8 literals will behave differently in C++20...
+# -Wno-deprecated-declarations: the library deprecated some functions
+# -Wno-documentation-unknown-command: code uses user-defined commands like @complexity
+# -Wno-exit-time-destructors: warning in json code triggered by NLOHMANN_JSON_SERIALIZE_ENUM
+# -Wno-float-equal: not all comparisons in the tests can be replaced by Approx
+# -Wno-keyword-macro: unit-tests use "#define private public"
 # -Wno-padded: padding is nothing to warn about
+# -Wno-range-loop-analysis: items tests "for(const auto i...)"
+# -Wno-switch-enum -Wno-covered-switch-default: pedantic/contradicting warnings about switches
+# -Wno-weak-vtables: exception class is defined inline, but has virtual method
 pedantic_clang:
-	$(MAKE) json_unit CXX=$(COMPILER_DIR)/clang++ CXXFLAGS=" \
+	rm -fr build_pedantic
+	CXXFLAGS=" \
 		-std=c++11 -Wno-c++98-compat -Wno-c++98-compat-pedantic \
 		-Werror \
 		-Weverything \
+		-Wno-c++2a-compat \
+		-Wno-deprecated-declarations \
 		-Wno-documentation-unknown-command \
 		-Wno-exit-time-destructors \
-		-Wno-keyword-macro \
-		-Wno-deprecated-declarations \
-		-Wno-weak-vtables \
-		-Wno-range-loop-analysis \
 		-Wno-float-equal \
+		-Wno-keyword-macro \
+		-Wno-padded \
+		-Wno-range-loop-analysis \
 		-Wno-switch-enum -Wno-covered-switch-default \
-		-Wno-c++2a-compat \
-		-Wno-c++17-extensions \
-		-Wno-padded"
+		-Wno-weak-vtables" cmake -S . -B build_pedantic -GNinja -DCMAKE_BUILD_TYPE=Debug -DJSON_MultipleHeaders=ON -DJSON_BuildTests=On
+	cmake --build build_pedantic
 
 # calling GCC with most warnings
 pedantic_gcc:
-	$(MAKE) json_unit CXX=$(COMPILER_DIR)/g++ CXXFLAGS=" \
+	rm -fr build_pedantic
+	CXXFLAGS=" \
 		-std=c++11 \
-		-Waddress \
-		-Waddress-of-packed-member \
-		-Waggressive-loop-optimizations \
-		-Waligned-new=all \
-		-Wall \
-		-Walloc-zero \
-		-Walloca \
-		-Warray-bounds \
-		-Warray-bounds=2 \
-		-Wattribute-alias=2 \
-		-Wattribute-warning \
-		-Wattributes \
-		-Wbool-compare \
-		-Wbool-operation \
-		-Wbuiltin-declaration-mismatch \
-		-Wbuiltin-macro-redefined \
-		-Wcannot-profile \
-		-Wcast-align \
-		-Wcast-function-type \
-		-Wcast-qual \
-		-Wcatch-value=3 \
-		-Wchar-subscripts \
-		-Wclass-conversion \
-		-Wclass-memaccess \
-		-Wclobbered \
-		-Wcomment \
-		-Wcomments \
-		-Wconditionally-supported \
-		-Wconversion \
-		-Wconversion-null \
-		-Wcoverage-mismatch \
-		-Wcpp \
-		-Wctor-dtor-privacy \
-		-Wdangling-else \
-		-Wdate-time \
-		-Wdelete-incomplete \
-		-Wdelete-non-virtual-dtor \
-		-Wdeprecated \
-		-Wdeprecated-copy \
-		-Wdeprecated-copy-dtor \
-		-Wdeprecated-declarations \
-		-Wdisabled-optimization \
-		-Wdiv-by-zero \
-		-Wdouble-promotion \
-		-Wduplicated-branches \
-		-Wduplicated-cond \
-		-Weffc++ \
-		-Wempty-body \
-		-Wendif-labels \
-		-Wenum-compare \
-		-Wexpansion-to-defined \
+		-pedantic \
 		-Werror \
-		-Wextra \
-		-Wextra-semi \
-		-Wfloat-conversion \
-		-Wfloat-equal \
-		-Wformat \
-		-Wformat-contains-nul \
-		-Wformat-extra-args \
-		-Wformat-nonliteral \
-		-Wformat-overflow=2 \
-		-Wformat-security \
-		-Wformat-signedness \
-		-Wformat-truncation=2 \
-		-Wformat-y2k \
-		-Wformat-zero-length \
-		-Wformat=2 \
-		-Wframe-address \
-		-Wfree-nonheap-object \
-		-Whsa \
-		-Wif-not-aligned \
-		-Wignored-attributes \
-		-Wignored-qualifiers \
-		-Wimplicit-fallthrough=5 \
-		-Winherited-variadic-ctor \
-		-Winit-list-lifetime \
-		-Winit-self \
-		-Winline \
-		-Wint-in-bool-context \
-		-Wint-to-pointer-cast \
-		-Winvalid-memory-model \
-		-Winvalid-offsetof \
-		-Winvalid-pch \
-		-Wliteral-suffix \
-		-Wlogical-not-parentheses \
-		-Wlogical-op \
-		-Wlto-type-mismatch \
-		-Wmain \
-		-Wmaybe-uninitialized \
-		-Wmemset-elt-size \
-		-Wmemset-transposed-args \
-		-Wmisleading-indentation \
-		-Wmissing-attributes \
-		-Wmissing-braces \
-		-Wmissing-declarations \
-		-Wmissing-field-initializers \
-		-Wmissing-format-attribute \
-		-Wmissing-include-dirs \
-		-Wmissing-noreturn \
-		-Wmissing-profile \
-		-Wmultichar \
-		-Wmultiple-inheritance \
-		-Wmultistatement-macros \
-		-Wnarrowing \
-		-Wno-deprecated-declarations \
-		-Wno-long-long \
-		-Wno-namespaces \
-		-Wno-padded \
-		-Wno-switch-enum \
-		-Wno-system-headers \
-		-Wno-templates \
-		-Wno-undef \
-		-Wnoexcept \
-		-Wnoexcept-type \
-		-Wnon-template-friend \
-		-Wnon-virtual-dtor \
-		-Wnonnull \
-		-Wnonnull-compare \
-		-Wnonportable-cfstrings \
-		-Wnormalized \
-		-Wnull-dereference \
-		-Wodr \
-		-Wold-style-cast \
-		-Wopenmp-simd \
-		-Woverflow \
-		-Woverlength-strings \
-		-Woverloaded-virtual \
-		-Wpacked \
-		-Wpacked-bitfield-compat \
-		-Wpacked-not-aligned \
-		-Wparentheses \
-		-Wpedantic \
-		-Wpessimizing-move \
-		-Wplacement-new=2 \
-		-Wpmf-conversions \
-		-Wpointer-arith \
-		-Wpointer-compare \
-		-Wpragmas \
-		-Wprio-ctor-dtor \
-		-Wpsabi \
-		-Wredundant-decls \
-		-Wredundant-move \
-		-Wregister \
-		-Wreorder \
-		-Wrestrict \
-		-Wreturn-local-addr \
-		-Wreturn-type \
-		-Wscalar-storage-order \
-		-Wsequence-point \
-		-Wshadow \
-		-Wshadow-compatible-local \
-		-Wshadow-local \
-		-Wshadow=compatible-local \
-		-Wshadow=global \
-		-Wshadow=local \
-		-Wshift-count-negative \
-		-Wshift-count-overflow \
-		-Wshift-negative-value \
-		-Wshift-overflow=2 \
-		-Wsign-compare \
-		-Wsign-conversion \
-		-Wsign-promo \
-		-Wsized-deallocation \
-		-Wsizeof-array-argument \
-		-Wsizeof-pointer-div \
-		-Wsizeof-pointer-memaccess \
-		-Wstack-protector \
-		-Wstrict-aliasing=3 \
-		-Wstrict-null-sentinel \
-		-Wstrict-overflow=5 \
-		-Wstringop-overflow=4 \
-		-Wstringop-truncation \
-		-Wsubobject-linkage \
-		-Wsuggest-attribute=cold \
-		-Wsuggest-attribute=const \
-		-Wsuggest-attribute=format \
-		-Wsuggest-attribute=malloc \
-		-Wsuggest-attribute=noreturn \
-		-Wsuggest-attribute=pure \
-		-Wsuggest-final-methods \
-		-Wsuggest-final-types \
-		-Wsuggest-override \
-		-Wswitch \
-		-Wswitch-bool \
-		-Wswitch-default \
-		-Wswitch-unreachable \
-		-Wsync-nand \
-		-Wsynth \
-		-Wtautological-compare \
-		-Wterminate \
-		-Wtrampolines \
-		-Wtrigraphs \
-		-Wtype-limits \
-		-Wuninitialized \
-		-Wunknown-pragmas \
-		-Wunreachable-code \
-		-Wunsafe-loop-optimizations \
-		-Wunused \
-		-Wunused-but-set-parameter \
-		-Wunused-but-set-variable \
-		-Wunused-const-variable=2 \
-		-Wunused-function \
-		-Wunused-label \
-		-Wunused-local-typedefs \
-		-Wunused-macros \
-		-Wunused-parameter \
-		-Wunused-result \
-		-Wunused-value \
-		-Wunused-variable \
-		-Wuseless-cast \
-		-Wvarargs \
-		-Wvariadic-macros \
-		-Wvector-operation-performance \
-		-Wvirtual-inheritance \
-		-Wvirtual-move-assign \
-		-Wvla \
-		-Wvolatile-register-var \
-		-Wwrite-strings \
-		-Wzero-as-null-pointer-constant \
-		"
+		--all-warnings                                    \
+		--extra-warnings                                  \
+		-W                                                \
+		-Wno-abi-tag                                         \
+		-Waddress                                         \
+		-Waddress-of-packed-member                        \
+		-Wno-aggregate-return                                \
+		-Waggressive-loop-optimizations                   \
+		-Waligned-new=all                                 \
+		-Wall                                             \
+		-Walloc-zero                                      \
+		-Walloca                                          \
+		-Wanalyzer-double-fclose                          \
+		-Wanalyzer-double-free                            \
+		-Wanalyzer-exposure-through-output-file           \
+		-Wanalyzer-file-leak                              \
+		-Wanalyzer-free-of-non-heap                       \
+		-Wanalyzer-malloc-leak                            \
+		-Wanalyzer-null-argument                          \
+		-Wanalyzer-null-dereference                       \
+		-Wanalyzer-possible-null-argument                 \
+		-Wanalyzer-possible-null-dereference              \
+		-Wanalyzer-stale-setjmp-buffer                    \
+		-Wanalyzer-tainted-array-index                    \
+		-Wanalyzer-too-complex                            \
+		-Wanalyzer-unsafe-call-within-signal-handler      \
+		-Wanalyzer-use-after-free                         \
+		-Wanalyzer-use-of-pointer-in-stale-stack-frame    \
+		-Warith-conversion                                \
+		-Warray-bounds                                    \
+		-Warray-bounds=2                                  \
+		-Wattribute-alias=2                               \
+		-Wattribute-warning                               \
+		-Wattributes                                      \
+		-Wbool-compare                                    \
+		-Wbool-operation                                  \
+		-Wbuiltin-declaration-mismatch                    \
+		-Wbuiltin-macro-redefined                         \
+		-Wc++0x-compat                                    \
+		-Wc++11-compat                                    \
+		-Wc++14-compat                                    \
+		-Wc++17-compat                                    \
+		-Wc++1z-compat                                    \
+		-Wc++20-compat                                    \
+		-Wc++2a-compat                                    \
+		-Wcannot-profile                                  \
+		-Wcast-align                                      \
+		-Wcast-align=strict                               \
+		-Wcast-function-type                              \
+		-Wcast-qual                                       \
+		-Wcatch-value=3                                   \
+		-Wchar-subscripts                                 \
+		-Wclass-conversion                                \
+		-Wclass-memaccess                                 \
+		-Wclobbered                                       \
+		-Wcomma-subscript                                 \
+		-Wcomment                                         \
+		-Wcomments                                        \
+		-Wconditionally-supported                         \
+		-Wconversion                                      \
+		-Wconversion-null                                 \
+		-Wcoverage-mismatch                               \
+		-Wcpp                                             \
+		-Wctor-dtor-privacy                               \
+		-Wdangling-else                                   \
+		-Wdate-time                                       \
+		-Wdelete-incomplete                               \
+		-Wdelete-non-virtual-dtor                         \
+		-Wdeprecated                                      \
+		-Wdeprecated-copy                                 \
+		-Wdeprecated-copy-dtor                            \
+		-Wdeprecated-declarations                         \
+		-Wdisabled-optimization                           \
+		-Wdiv-by-zero                                     \
+		-Wdouble-promotion                                \
+		-Wduplicated-branches                             \
+		-Wduplicated-cond                                 \
+		-Weffc++                                          \
+		-Wempty-body                                      \
+		-Wendif-labels                                    \
+		-Wenum-compare                                    \
+		-Wexpansion-to-defined                            \
+		-Wextra                                           \
+		-Wextra-semi                                      \
+		-Wfloat-conversion                                \
+		-Wfloat-equal                                     \
+		-Wformat -Wformat-contains-nul                    \
+		-Wformat -Wformat-extra-args                      \
+		-Wformat -Wformat-nonliteral                      \
+		-Wformat -Wformat-security                        \
+		-Wformat -Wformat-y2k                             \
+		-Wformat -Wformat-zero-length                     \
+		-Wformat-diag                                     \
+		-Wformat-overflow=2                               \
+		-Wformat-signedness                               \
+		-Wformat-truncation=2                             \
+		-Wformat=2                                        \
+		-Wframe-address                                   \
+		-Wfree-nonheap-object                             \
+		-Whsa                                             \
+		-Wif-not-aligned                                  \
+		-Wignored-attributes                              \
+		-Wignored-qualifiers                              \
+		-Wimplicit-fallthrough=5                          \
+		-Winaccessible-base                               \
+		-Winherited-variadic-ctor                         \
+		-Winit-list-lifetime                              \
+		-Winit-self                                       \
+		-Winline                                          \
+		-Wint-in-bool-context                             \
+		-Wint-to-pointer-cast                             \
+		-Winvalid-memory-model                            \
+		-Winvalid-offsetof                                \
+		-Winvalid-pch                                     \
+		-Wliteral-suffix                                  \
+		-Wlogical-not-parentheses                         \
+		-Wlogical-op                                      \
+		-Wno-long-long                                       \
+		-Wlto-type-mismatch                               \
+		-Wmain                                            \
+		-Wmaybe-uninitialized                             \
+		-Wmemset-elt-size                                 \
+		-Wmemset-transposed-args                          \
+		-Wmisleading-indentation                          \
+		-Wmismatched-tags                                 \
+		-Wmissing-attributes                              \
+		-Wmissing-braces                                  \
+		-Wmissing-declarations                            \
+		-Wmissing-field-initializers                      \
+		-Wmissing-include-dirs                            \
+		-Wmissing-profile                                 \
+		-Wmultichar                                       \
+		-Wmultiple-inheritance                            \
+		-Wmultistatement-macros                           \
+		-Wno-namespaces                                      \
+		-Wnarrowing                                       \
+		-Wno-noexcept                                        \
+		-Wnoexcept-type                                   \
+		-Wnon-template-friend                             \
+		-Wnon-virtual-dtor                                \
+		-Wnonnull                                         \
+		-Wnonnull-compare                                 \
+		-Wnonportable-cfstrings                           \
+		-Wnormalized=nfkc                                 \
+		-Wnull-dereference                                \
+		-Wodr                                             \
+		-Wold-style-cast                                  \
+		-Wopenmp-simd                                     \
+		-Woverflow                                        \
+		-Woverlength-strings                              \
+		-Woverloaded-virtual                              \
+		-Wpacked                                          \
+		-Wpacked-bitfield-compat                          \
+		-Wpacked-not-aligned                              \
+		-Wno-padded                                          \
+		-Wparentheses                                     \
+		-Wpedantic                                        \
+		-Wpessimizing-move                                \
+		-Wplacement-new=2                                 \
+		-Wpmf-conversions                                 \
+		-Wpointer-arith                                   \
+		-Wpointer-compare                                 \
+		-Wpragmas                                         \
+		-Wprio-ctor-dtor                                  \
+		-Wpsabi                                           \
+		-Wredundant-decls                                 \
+		-Wredundant-move                                  \
+		-Wredundant-tags                                  \
+		-Wregister                                        \
+		-Wreorder                                         \
+		-Wrestrict                                        \
+		-Wreturn-local-addr                               \
+		-Wreturn-type                                     \
+		-Wscalar-storage-order                            \
+		-Wsequence-point                                  \
+		-Wshadow=compatible-local                         \
+		-Wshadow=global                                   \
+		-Wshadow=local                                    \
+		-Wshift-count-negative                            \
+		-Wshift-count-overflow                            \
+		-Wshift-negative-value                            \
+		-Wshift-overflow=2                                \
+		-Wsign-compare                                    \
+		-Wsign-conversion                                 \
+		-Wsign-promo                                      \
+		-Wsized-deallocation                              \
+		-Wsizeof-array-argument                           \
+		-Wsizeof-pointer-div                              \
+		-Wsizeof-pointer-memaccess                        \
+		-Wstack-protector                                 \
+		-Wstrict-aliasing                                 \
+		-Wstrict-aliasing=3                               \
+		-Wstrict-null-sentinel                            \
+		-Wstrict-overflow                                 \
+		-Wstrict-overflow=5                               \
+		-Wstring-compare                                  \
+		-Wstringop-overflow                               \
+		-Wstringop-overflow=4                             \
+		-Wstringop-truncation                             \
+		-Wsubobject-linkage                               \
+		-Wsuggest-attribute=cold                          \
+		-Wsuggest-attribute=const                         \
+		-Wsuggest-attribute=format                        \
+		-Wsuggest-attribute=malloc                        \
+		-Wsuggest-attribute=noreturn                      \
+		-Wsuggest-attribute=pure                          \
+		-Wsuggest-final-methods                           \
+		-Wsuggest-final-types                             \
+		-Wsuggest-override                                \
+		-Wswitch                                          \
+		-Wswitch-bool                                     \
+		-Wswitch-default                                  \
+		-Wno-switch-enum                                     \
+		-Wswitch-outside-range                            \
+		-Wswitch-unreachable                              \
+		-Wsync-nand                                       \
+		-Wsynth                                           \
+		-Wno-system-headers                                  \
+		-Wtautological-compare                            \
+		-Wno-templates                                       \
+		-Wterminate                                       \
+		-Wtrampolines                                     \
+		-Wtrigraphs                                       \
+		-Wtype-limits                                     \
+		-Wundef                                           \
+		-Wuninitialized                                   \
+		-Wunknown-pragmas                                 \
+		-Wunreachable-code                                \
+		-Wunsafe-loop-optimizations                       \
+		-Wunused                                          \
+		-Wunused-but-set-parameter                        \
+		-Wunused-but-set-variable                         \
+		-Wunused-const-variable=2                         \
+		-Wunused-function                                 \
+		-Wunused-label                                    \
+		-Wno-unused-local-typedefs                           \
+		-Wunused-macros                                   \
+		-Wunused-parameter                                \
+		-Wunused-result                                   \
+		-Wunused-value                                    \
+		-Wunused-variable                                 \
+		-Wuseless-cast                                    \
+		-Wvarargs                                         \
+		-Wvariadic-macros                                 \
+		-Wvector-operation-performance                    \
+		-Wvirtual-inheritance                             \
+		-Wvirtual-move-assign                             \
+		-Wvla                                             \
+		-Wvolatile                                        \
+		-Wvolatile-register-var                           \
+		-Wwrite-strings                                   \
+		-Wzero-as-null-pointer-constant                   \
+		-Wzero-length-bounds                              \
+		" cmake -S . -B build_pedantic -GNinja -DCMAKE_BUILD_TYPE=Debug -DJSON_MultipleHeaders=ON -DJSON_BuildTests=On
+	cmake --build build_pedantic
 
 ##########################################################################
 # benchmarks
 ##########################################################################
 
 run_benchmarks:
+	rm -fr build_benchmarks
 	mkdir build_benchmarks
-	cd build_benchmarks ; cmake ../benchmarks
-	cd build_benchmarks ; make
+	cd build_benchmarks ; cmake ../benchmarks -GNinja -DCMAKE_BUILD_TYPE=Release -DJSON_BuildTests=On
+	cd build_benchmarks ; ninja
 	cd build_benchmarks ; ./json_benchmarks
 
 ##########################################################################
@@ -436,28 +452,39 @@ fuzzing-stop:
 	-killall fuzzer
 	-killall afl-fuzz
 
+
 ##########################################################################
-# static analyzer
+# Static analysis
 ##########################################################################
 
-# call cppcheck on the main header file
+# call cppcheck <http://cppcheck.sourceforge.net>
+# Note: this target is called by Travis
 cppcheck:
-	cppcheck --enable=warning --inline-suppr --inconclusive --force --std=c++11 $(SRCS) --error-exitcode=1
+	cppcheck --enable=warning --inline-suppr --inconclusive --force --std=c++11 $(AMALGAMATED_FILE) --error-exitcode=1
 
-# compile and check with Clang Static Analyzer
+# call Clang Static Analyzer <https://clang-analyzer.llvm.org>
 clang_analyze:
 	rm -fr clang_analyze_build
 	mkdir clang_analyze_build
-	cd clang_analyze_build ; CCC_CXX=$(COMPILER_DIR)/clang++ CXX=$(COMPILER_DIR)/clang++ $(COMPILER_DIR)/scan-build cmake .. -GNinja
-	cd clang_analyze_build ; $(COMPILER_DIR)/scan-build -enable-checker alpha.core.BoolAssignment,alpha.core.CallAndMessageUnInitRefArg,alpha.core.CastSize,alpha.core.CastToStruct,alpha.core.Conversion,alpha.core.DynamicTypeChecker,alpha.core.FixedAddr,alpha.core.PointerArithm,alpha.core.PointerSub,alpha.core.SizeofPtr,alpha.core.StackAddressAsyncEscape,alpha.core.TestAfterDivZero,alpha.deadcode.UnreachableCode,core.builtin.BuiltinFunctions,core.builtin.NoReturnFunctions,core.CallAndMessage,core.DivideZero,core.DynamicTypePropagation,core.NonnilStringConstants,core.NonNullParamChecker,core.NullDereference,core.StackAddressEscape,core.UndefinedBinaryOperatorResult,core.uninitialized.ArraySubscript,core.uninitialized.Assign,core.uninitialized.Branch,core.uninitialized.CapturedBlockVariable,core.uninitialized.UndefReturn,core.VLASize,cplusplus.InnerPointer,cplusplus.Move,cplusplus.NewDelete,cplusplus.NewDeleteLeaks,cplusplus.SelfAssignment,deadcode.DeadStores,nullability.NullableDereferenced,nullability.NullablePassedToNonnull,nullability.NullableReturnedFromNonnull,nullability.NullPassedToNonnull,nullability.NullReturnedFromNonnull --use-c++=$(COMPILER_DIR)/clang++ --view -analyze-headers -o clang_analyze_build/report.html ninja
+	cd clang_analyze_build ; CCC_CXX=$(COMPILER_DIR)/clang++ CXX=$(COMPILER_DIR)/clang++ $(COMPILER_DIR)/scan-build cmake .. -GNinja -DJSON_BuildTests=On
+	cd clang_analyze_build ; \
+		$(COMPILER_DIR)/scan-build \
+			-enable-checker alpha.core.BoolAssignment,alpha.core.CallAndMessageUnInitRefArg,alpha.core.CastSize,alpha.core.CastToStruct,alpha.core.Conversion,alpha.core.DynamicTypeChecker,alpha.core.FixedAddr,alpha.core.PointerArithm,alpha.core.PointerSub,alpha.core.SizeofPtr,alpha.core.StackAddressAsyncEscape,alpha.core.TestAfterDivZero,alpha.deadcode.UnreachableCode,core.builtin.BuiltinFunctions,core.builtin.NoReturnFunctions,core.CallAndMessage,core.DivideZero,core.DynamicTypePropagation,core.NonnilStringConstants,core.NonNullParamChecker,core.NullDereference,core.StackAddressEscape,core.UndefinedBinaryOperatorResult,core.uninitialized.ArraySubscript,core.uninitialized.Assign,core.uninitialized.Branch,core.uninitialized.CapturedBlockVariable,core.uninitialized.UndefReturn,core.VLASize,cplusplus.InnerPointer,cplusplus.Move,cplusplus.NewDelete,cplusplus.NewDeleteLeaks,cplusplus.SelfAssignment,deadcode.DeadStores,nullability.NullableDereferenced,nullability.NullablePassedToNonnull,nullability.NullableReturnedFromNonnull,nullability.NullPassedToNonnull,nullability.NullReturnedFromNonnull \
+			--use-c++=$(COMPILER_DIR)/clang++ -analyze-headers -o report ninja
+	open clang_analyze_build/report/*/index.html
 
-# call cpplint (some errors expected due to false positives)
+# call cpplint <https://github.com/cpplint/cpplint>
+# Note: some errors expected due to false positives
 cpplint:
-	third_party/cpplint/cpplint.py --filter=-whitespace,-legal,-readability/alt_tokens,-runtime/references,-runtime/explicit --quiet --recursive include
+	third_party/cpplint/cpplint.py \
+		--filter=-whitespace,-legal,-readability/alt_tokens,-runtime/references,-runtime/explicit \
+		--quiet --recursive $(SRCS)
 
+# call Clang-Tidy <https://clang.llvm.org/extra/clang-tidy/>
 clang_tidy:
-	$(COMPILER_DIR)/clang-tidy $(SRCS) -- -Iinclude -std=c++11
+	$(COMPILER_DIR)/clang-tidy $(AMALGAMATED_FILE) -- -Iinclude -std=c++11
 
+# call PVS-Studio Analyzer <https://www.viva64.com/en/pvs-studio/>
 pvs_studio:
 	rm -fr pvs_studio_build
 	mkdir pvs_studio_build
@@ -466,45 +493,70 @@ pvs_studio:
 	cd pvs_studio_build ; plog-converter -a'GA:1,2;64:1;CS' -t fullhtml PVS-Studio.log -o pvs
 	open pvs_studio_build/pvs/index.html
 
+# call Infer <https://fbinfer.com> static analyzer
 infer:
 	rm -fr infer_build
 	mkdir infer_build
 	cd infer_build ; infer compile -- cmake .. ; infer run -- make -j 4
 
+# call OCLint <http://oclint.org> static analyzer
 oclint:
 	oclint $(SRCS) -report-type html -enable-global-analysis -o oclint_report.html -max-priority-1=10000 -max-priority-2=10000 -max-priority-3=10000 -- -std=c++11 -Iinclude
 	open oclint_report.html
 
+# execute the test suite with Clang sanitizers (address and undefined behavior)
+clang_sanitize:
+	rm -fr clang_sanitize_build
+	mkdir clang_sanitize_build
+	cd clang_sanitize_build ; CXX=$(COMPILER_DIR)/clang++ cmake .. -DJSON_Sanitizer=On -DJSON_MultipleHeaders=ON -DJSON_BuildTests=On -GNinja
+	cd clang_sanitize_build ; ninja
+	cd clang_sanitize_build ; ctest -j10
+
+
 ##########################################################################
-# maintainer targets
+# Code format and source amalgamation
 ##########################################################################
 
-# pretty printer
+# call the Artistic Style pretty printer on all source files
 pretty:
-	astyle --style=allman --indent=spaces=4 --indent-modifiers \
-	   --indent-switches --indent-preproc-block --indent-preproc-define \
-	   --indent-col1-comments --pad-oper --pad-header --align-pointer=type \
-	   --align-reference=type --add-brackets --convert-tabs --close-templates \
-	   --lineend=linux --preserve-date --suffix=none --formatted \
-	   $(SRCS) $(AMALGAMATED_FILE) test/src/*.cpp \
-	   benchmarks/src/benchmarks.cpp doc/examples/*.cpp
+	astyle \
+		--style=allman \
+		--indent=spaces=4 \
+		--indent-modifiers \
+	    --indent-switches \
+	    --indent-preproc-block \
+	    --indent-preproc-define \
+	    --indent-col1-comments \
+	    --pad-oper \
+	    --pad-header \
+	    --align-pointer=type \
+	    --align-reference=type \
+	    --add-brackets \
+	    --convert-tabs \
+	    --close-templates \
+	    --lineend=linux \
+	    --preserve-date \
+	    --suffix=none \
+	    --formatted \
+	   $(SRCS) $(AMALGAMATED_FILE) test/src/*.cpp benchmarks/src/benchmarks.cpp doc/examples/*.cpp
 
 # create single header file
 amalgamate: $(AMALGAMATED_FILE)
 
+# call the amalgamation tool and pretty print
 $(AMALGAMATED_FILE): $(SRCS)
 	third_party/amalgamate/amalgamate.py -c third_party/amalgamate/config.json -s . --verbose=yes
 	$(MAKE) pretty
 
-# check if single_include/nlohmann/json.hpp has been amalgamated from the nlohmann sources
+# check if file single_include/nlohmann/json.hpp has been amalgamated from the nlohmann sources
+# Note: this target is called by Travis
 check-amalgamation:
 	@mv $(AMALGAMATED_FILE) $(AMALGAMATED_FILE)~
 	@$(MAKE) amalgamate
 	@diff $(AMALGAMATED_FILE) $(AMALGAMATED_FILE)~ || (echo "===================================================================\n  Amalgamation required! Please read the contribution guidelines\n  in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_FILE)~ $(AMALGAMATED_FILE) ; false)
 	@mv $(AMALGAMATED_FILE)~ $(AMALGAMATED_FILE)
 
-# check if every header in nlohmann includes sufficient headers to be compiled
-# individually
+# check if every header in nlohmann includes sufficient headers to be compiled individually
 check-single-includes:
 	@for x in $(SRCS); do \
 	  echo "Checking self-sufficiency of $$x..." ; \
@@ -513,29 +565,90 @@ check-single-includes:
 	  rm -f single_include_test.cpp single_include_test; \
 	done
 
+
 ##########################################################################
-# changelog
+# CMake
 ##########################################################################
 
+# grep "^option" CMakeLists.txt test/CMakeLists.txt | sed 's/(/ /' | awk '{print $2}' | xargs
+
+# check if all flags of our CMake files work
+check_cmake_flags_do:
+	$(CMAKE_BINARY) --version
+	for flag in '' JSON_BuildTests JSON_Install JSON_MultipleHeaders JSON_Sanitizer JSON_Valgrind JSON_NoExceptions JSON_Coverage; do \
+		rm -fr cmake_build; \
+		mkdir cmake_build; \
+		echo "$(CMAKE_BINARY) .. -D$$flag=On" ; \
+		cd cmake_build ; \
+		CXX=g++-8 $(CMAKE_BINARY) .. -D$$flag=On -DCMAKE_CXX_COMPILE_FEATURES="cxx_std_11;cxx_range_for" -DCMAKE_CXX_FLAGS="-std=gnu++11" ; \
+		test -f Makefile || exit 1 ; \
+		cd .. ; \
+	done;
+
+# call target `check_cmake_flags_do` twice: once for minimal required CMake version 3.1.0 and once for the installed version
+check_cmake_flags:
+	wget https://github.com/Kitware/CMake/releases/download/v3.1.0/cmake-3.1.0-Darwin64.tar.gz
+	tar xfz cmake-3.1.0-Darwin64.tar.gz
+	CMAKE_BINARY=$(abspath cmake-3.1.0-Darwin64/CMake.app/Contents/bin/cmake) $(MAKE) check_cmake_flags_do
+	CMAKE_BINARY=$(shell which cmake) $(MAKE) check_cmake_flags_do
+
+
+##########################################################################
+# ChangeLog
+##########################################################################
+
+# Create a ChangeLog based on the git log using the GitHub Changelog Generator
+# (<https://github.com/github-changelog-generator/github-changelog-generator>).
+
+# variable to control the diffs between the last released version and the current repository state
 NEXT_VERSION ?= "unreleased"
 
 ChangeLog.md:
-	github_changelog_generator -o ChangeLog.md --simple-list --release-url https://github.com/nlohmann/json/releases/tag/%s --future-release $(NEXT_VERSION)
-	gsed -i 's|https://github.com/nlohmann/json/releases/tag/HEAD|https://github.com/nlohmann/json/tree/HEAD|' ChangeLog.md
-	gsed -i '2i All notable changes to this project will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org/).' ChangeLog.md
+	github_changelog_generator -o ChangeLog.md --user nlohmann --project json --simple-list --release-url https://github.com/nlohmann/json/releases/tag/%s --future-release $(NEXT_VERSION)
+	$(SED) -i 's|https://github.com/nlohmann/json/releases/tag/HEAD|https://github.com/nlohmann/json/tree/HEAD|' ChangeLog.md
+	$(SED) -i '2i All notable changes to this project will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org/).' ChangeLog.md
 
 
 ##########################################################################
-# release
+# Release files
 ##########################################################################
 
+# Create the files for a release and add signatures and hashes. We use `-X` to make the resulting ZIP file
+# reproducible, see <https://content.pivotal.io/blog/barriers-to-deterministic-reproducible-zip-files>.
+
 release:
+	rm -fr release_files
 	mkdir release_files
-	zip -9 -r include.zip include/*
+	zip -9 --recurse-paths -X include.zip $(SRCS) $(AMALGAMATED_FILE) meson.build
 	gpg --armor --detach-sig include.zip
 	mv include.zip include.zip.asc release_files
-	gpg --armor --detach-sig single_include/nlohmann/json.hpp
-	cp single_include/nlohmann/json.hpp release_files
-	mv single_include/nlohmann/json.hpp.asc release_files
+	gpg --armor --detach-sig $(AMALGAMATED_FILE)
+	cp $(AMALGAMATED_FILE) release_files
+	mv $(AMALGAMATED_FILE).asc release_files
 	cd release_files ; shasum -a 256 json.hpp > hashes.txt
 	cd release_files ; shasum -a 256 include.zip >> hashes.txt
+
+
+##########################################################################
+# Maintenance
+##########################################################################
+
+# clean up
+clean:
+	rm -fr json_unit json_benchmarks fuzz fuzz-testing *.dSYM test/*.dSYM oclint_report.html
+	rm -fr benchmarks/files/numbers/*.json
+	rm -fr cmake-3.1.0-Darwin64.tar.gz cmake-3.1.0-Darwin64
+	rm -fr build_coverage build_benchmarks fuzz-testing clang_analyze_build pvs_studio_build infer_build clang_sanitize_build cmake_build
+	$(MAKE) clean -Cdoc
+	$(MAKE) clean -Ctest
+
+##########################################################################
+# Thirdparty code
+##########################################################################
+
+update_hedley:
+	rm -f include/nlohmann/thirdparty/hedley/hedley.hpp include/nlohmann/thirdparty/hedley/hedley_undef.hpp
+	curl https://raw.githubusercontent.com/nemequ/hedley/master/hedley.h -o include/nlohmann/thirdparty/hedley/hedley.hpp
+	gsed -i 's/HEDLEY_/JSON_HEDLEY_/g' include/nlohmann/thirdparty/hedley/hedley.hpp
+	grep "[[:blank:]]*#[[:blank:]]*undef" include/nlohmann/thirdparty/hedley/hedley.hpp | grep -v "__" | sort | uniq | gsed 's/ //g' | gsed 's/undef/undef /g' > include/nlohmann/thirdparty/hedley/hedley_undef.hpp
+	$(MAKE) amalgamate

README.md

@@ -2,19 +2,28 @@
 
 [![Build Status](https://travis-ci.org/nlohmann/json.svg?branch=master)](https://travis-ci.org/nlohmann/json)
 [![Build Status](https://ci.appveyor.com/api/projects/status/1acb366xfyg3qybk/branch/develop?svg=true)](https://ci.appveyor.com/project/nlohmann/json)
-[![Coverage Status](https://img.shields.io/coveralls/nlohmann/json.svg)](https://coveralls.io/r/nlohmann/json)
+[![Ubuntu](https://github.com/nlohmann/json/workflows/Ubuntu/badge.svg)](https://github.com/nlohmann/json/actions?query=workflow%3AUbuntu)
+[![macOS](https://github.com/nlohmann/json/workflows/macOS/badge.svg)](https://github.com/nlohmann/json/actions?query=workflow%3AmacOS)
+[![Windows](https://github.com/nlohmann/json/workflows/Windows/badge.svg)](https://github.com/nlohmann/json/actions?query=workflow%3AWindows)
+[![Build Status](https://circleci.com/gh/nlohmann/json.svg?style=svg)](https://circleci.com/gh/nlohmann/json)
+[![Coverage Status](https://coveralls.io/repos/github/nlohmann/json/badge.svg?branch=develop)](https://coveralls.io/github/nlohmann/json?branch=develop)
 [![Coverity Scan Build Status](https://scan.coverity.com/projects/5550/badge.svg)](https://scan.coverity.com/projects/nlohmann-json)
 [![Codacy Badge](https://api.codacy.com/project/badge/Grade/f3732b3327e34358a0e9d1fe9f661f08)](https://www.codacy.com/app/nlohmann/json?utm_source=github.com&utm_medium=referral&utm_content=nlohmann/json&utm_campaign=Badge_Grade)
 [![Language grade: C/C++](https://img.shields.io/lgtm/grade/cpp/g/nlohmann/json.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/nlohmann/json/context:cpp)
-[![Try online](https://img.shields.io/badge/try-online-blue.svg)](https://wandbox.org/permlink/TarF5pPn9NtHQjhf)
-[![Documentation](https://img.shields.io/badge/docs-doxygen-blue.svg)](http://nlohmann.github.io/json)
+[![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/3lCHrFUZANONKv7a)
+[![Documentation](https://img.shields.io/badge/docs-doxygen-blue.svg)](https://nlohmann.github.io/json/doxygen/index.html)
 [![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
+[![FOSSA Status](https://app.fossa.com/api/projects/git%2Bgithub.com%2Fnlohmann%2Fjson.svg?type=shield)](https://app.fossa.com/projects/git%2Bgithub.com%2Fnlohmann%2Fjson?ref=badge_shield)
 [![GitHub Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
-[![GitHub Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](http://github.com/nlohmann/json/issues)
-[![Average time to resolve an issue](http://isitmaintained.com/badge/resolution/nlohmann/json.svg)](http://isitmaintained.com/project/nlohmann/json "Average time to resolve an issue")
+[![GitHub Downloads](https://img.shields.io/github/downloads/nlohmann/json/total)](https://github.com/nlohmann/json/releases)
+[![GitHub Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](https://github.com/nlohmann/json/issues)
+[![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)
+[![GitHub Sponsors](https://img.shields.io/badge/GitHub-Sponsors-ff69b4)](https://github.com/sponsors/nlohmann)
 
 - [Design goals](#design-goals)
+- [Sponsors](#sponsors)
 - [Integration](#integration)
   - [CMake](#cmake)
   - [Package Managers](#package-managers)
@@ -40,13 +49,13 @@
 
 ## Design goals
 
-There are myriads of [JSON](http://json.org) libraries out there, and each may even have its reason to exist. Our class had these design goals:
+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.
 
 - **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.
 
-- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/tree/develop/test/src) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](http://valgrind.org) and the [Clang Sanitizers](https://clang.llvm.org/docs/index.html) that there are no memory leaks. [Google OSS-Fuzz](https://github.com/google/oss-fuzz/tree/master/projects/json) additionally runs fuzz tests against all parsers 24/7, effectively executing billions of tests so far. To maintain high quality, the project is following the [Core Infrastructure Initiative (CII) best practices](https://bestpractices.coreinfrastructure.org/projects/289).
+- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/tree/develop/test/src) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](https://valgrind.org) and the [Clang Sanitizers](https://clang.llvm.org/docs/index.html) that there are no memory leaks. [Google OSS-Fuzz](https://github.com/google/oss-fuzz/tree/master/projects/json) additionally runs fuzz tests against all parsers 24/7, effectively executing billions of tests so far. To maintain high quality, the project is following the [Core Infrastructure Initiative (CII) best practices](https://bestpractices.coreinfrastructure.org/projects/289).
 
 Other aspects were not so important to us:
 
@@ -57,6 +66,19 @@ Other aspects were not so important to us:
 See the [contribution guidelines](https://github.com/nlohmann/json/blob/master/.github/CONTRIBUTING.md#please-dont) for more information.
 
 
+## Sponsors
+
+You can sponsor this library at [GitHub Sponsors](https://github.com/sponsors/nlohmann).
+
+### :label: Named Sponsors
+
+- [Michael Hartmann](https://github.com/reFX-Mike)
+- [Stefan Hagen](https://github.com/sthagen)
+- [Steve Sperandeo](https://github.com/homer6)
+
+Thanks everyone!
+
+
 ## Integration
 
 [`json.hpp`](https://github.com/nlohmann/json/blob/develop/single_include/nlohmann/json.hpp) is the single required file in `single_include/nlohmann` or [released here](https://github.com/nlohmann/json/releases). You need to add
@@ -115,6 +137,34 @@ add_library(foo ...)
 target_link_libraries(foo PRIVATE nlohmann_json::nlohmann_json)
 ```
 
+##### Embedded (FetchContent)
+
+Since CMake v3.11,
+[FetchContent](https://cmake.org/cmake/help/v3.11/module/FetchContent.html) can
+be used to automatically download the repository as a dependency at configure type.
+
+Example:
+```cmake
+include(FetchContent)
+
+FetchContent_Declare(json
+  GIT_REPOSITORY https://github.com/nlohmann/json.git
+  GIT_TAG v3.7.3)
+
+FetchContent_GetProperties(json)
+if(NOT json_POPULATED)
+  FetchContent_Populate(json)
+  add_subdirectory(${json_SOURCE_DIR} ${json_BINARY_DIR} EXCLUDE_FROM_ALL)
+endif()
+
+target_link_libraries(foo PRIVATE nlohmann_json::nlohmann_json)
+```
+
+**Note**: The repository https://github.com/nlohmann/json download size is huge.
+It contains all the dataset used for the benchmarks. You might want to depend on
+a smaller repository. For instance, you might want to replace the URL above by
+https://github.com/ArthurSonzogni/nlohmann_json_cmake_fetchcontent
+
 #### Supporting Both
 
 To allow your project to support either an externally supplied or an embedded JSON library, you can use a pattern akin to the following:
@@ -149,21 +199,23 @@ endif()
 
 ### Package Managers
 
-:beer: If you are using OS X and [Homebrew](http://brew.sh), just type `brew tap nlohmann/json` and `brew install nlohmann_json` and you're set. If you want the bleeding edge rather than the latest release, use `brew install nlohmann_json --HEAD`.
+:beer: If you are using OS X and [Homebrew](https://brew.sh), just type `brew tap nlohmann/json` and `brew install nlohmann-json` and you're set. If you want the bleeding edge rather than the latest release, use `brew install nlohmann-json --HEAD`.
 
-If you are using the [Meson Build System](http://mesonbuild.com), then you can get a wrap file by downloading it from [Meson WrapDB](https://wrapdb.mesonbuild.com/nlohmann_json), or simply use `meson wrap install nlohmann_json`.
+If you are using the [Meson Build System](https://mesonbuild.com), add this source tree as a [meson subproject](https://mesonbuild.com/Subprojects.html#using-a-subproject). You may also use the `include.zip` published in this project's [Releases](https://github.com/nlohmann/json/releases) to reduce the size of the vendored source tree. Alternatively, you can get a wrap file by downloading it from [Meson WrapDB](https://wrapdb.mesonbuild.com/nlohmann_json), or simply use `meson wrap install nlohmann_json`. Please see the meson project for any issues regarding the packaging.
 
-If you are using [Conan](https://www.conan.io/) to manage your dependencies, merely add `jsonformoderncpp/x.y.z@vthiery/stable` to your `conanfile.py`'s requires, where `x.y.z` is the release version you want to use. Please file issues [here](https://github.com/vthiery/conan-jsonformoderncpp/issues) if you experience problems with the packages.
+The provided meson.build can also be used as an alternative to cmake for installing `nlohmann_json` system-wide in which case a pkg-config file is installed. To use it, simply have your build system require the `nlohmann_json` pkg-config dependency. In Meson, it is preferred to use the [`dependency()`](https://mesonbuild.com/Reference-manual.html#dependency) object with a subproject fallback, rather than using the subproject directly.
 
-If you are using [Spack](https://www.spack.io/) to manage your dependencies, you can use the `nlohmann_json` package. Please see the [spack project](https://github.com/spack/spack) for any issues regarding the packaging.
+If you are using [Conan](https://www.conan.io/) to manage your dependencies, merely add `nlohmann_json/x.y.z` to your `conanfile`'s requires, where `x.y.z` is the release version you want to use. Please file issues [here](https://github.com/conan-io/conan-center-index/issues) if you experience problems with the packages.
 
-If you are using [hunter](https://github.com/ruslo/hunter/) on your project for external dependencies, then you can use the [nlohmann_json package](https://docs.hunter.sh/en/latest/packages/pkg/nlohmann_json.html). Please see the hunter project for any issues regarding the packaging.
+If you are using [Spack](https://www.spack.io/) to manage your dependencies, you can use the [`nlohmann-json` package](https://spack.readthedocs.io/en/latest/package_list.html#nlohmann-json). Please see the [spack project](https://github.com/spack/spack) for any issues regarding the packaging.
+
+If you are using [hunter](https://github.com/cpp-pm/hunter) on your project for external dependencies, then you can use the [nlohmann_json package](https://hunter.readthedocs.io/en/latest/packages/pkg/nlohmann_json.html). Please see the hunter project for any issues regarding the packaging.
 
 If you are using [Buckaroo](https://buckaroo.pm), you can install this library's module with `buckaroo add github.com/buckaroo-pm/nlohmann-json`. Please file issues [here](https://github.com/buckaroo-pm/nlohmann-json). There is a demo repo [here](https://github.com/njlr/buckaroo-nholmann-json-example).
 
 If you are using [vcpkg](https://github.com/Microsoft/vcpkg/) on your project for external dependencies, then you can use the [nlohmann-json package](https://github.com/Microsoft/vcpkg/tree/master/ports/nlohmann-json). Please see the vcpkg project for any issues regarding the packaging.
 
-If you are using [cget](http://cget.readthedocs.io/en/latest/), you can install the latest development version with `cget install nlohmann/json`. A specific version can be installed with `cget install nlohmann/json@v3.1.0`. Also, the multiple header version can be installed by adding the `-DJSON_MultipleHeaders=ON` flag (i.e., `cget install nlohmann/json -DJSON_MultipleHeaders=ON`).
+If you are using [cget](https://cget.readthedocs.io/en/latest/), you can install the latest development version with `cget install nlohmann/json`. A specific version can be installed with `cget install nlohmann/json@v3.1.0`. Also, the multiple header version can be installed by adding the `-DJSON_MultipleHeaders=ON` flag (i.e., `cget install nlohmann/json -DJSON_MultipleHeaders=ON`).
 
 If you are using [CocoaPods](https://cocoapods.org), you can use the library by adding pod `"nlohmann_json", '~>3.1.2'` to your podfile (see [an example](https://bitbucket.org/benman/nlohmann_json-cocoapod/src/master/)). Please file issues [here](https://bitbucket.org/benman/nlohmann_json-cocoapod/issues?status=new&status=open).
 
@@ -171,6 +223,13 @@ If you are using [NuGet](https://www.nuget.org), you can use the package [nlohma
 
 If you are using [conda](https://conda.io/), you can use the package [nlohmann_json](https://github.com/conda-forge/nlohmann_json-feedstock) from [conda-forge](https://conda-forge.org) executing `conda install -c conda-forge nlohmann_json`. Please file issues [here](https://github.com/conda-forge/nlohmann_json-feedstock/issues).
 
+If you are using [MSYS2](https://www.msys2.org/), your can use the [mingw-w64-nlohmann-json](https://packages.msys2.org/base/mingw-w64-nlohmann-json) package, just type `pacman -S mingw-w64-i686-nlohmann-json` or `pacman -S mingw-w64-x86_64-nlohmann-json` for installation. Please file issues [here](https://github.com/msys2/MINGW-packages/issues/new?title=%5Bnlohmann-json%5D) if you experience problems with the packages.
+
+If you are using [`build2`](https://build2.org), you can use the [`nlohmann-json`](https://cppget.org/nlohmann-json) package from the public repository https://cppget.org or directly from the [package's sources repository](https://github.com/build2-packaging/nlohmann-json). In your project's `manifest` file, just add `depends: nlohmann-json` (probably with some [version constraints](https://build2.org/build2-toolchain/doc/build2-toolchain-intro.xhtml#guide-add-remove-deps)). If you are not familiar with using dependencies in `build2`, [please read this introduction](https://build2.org/build2-toolchain/doc/build2-toolchain-intro.xhtml).
+Please file issues [here](https://github.com/build2-packaging/nlohmann-json) if you experience problems with the packages.
+
+If you are using [`wsjcpp`](https://wsjcpp.org), you can use the command `wsjcpp install "https://github.com/nlohmann/json:develop"` to get the latest version. Note you can change the branch ":develop" to an existing tag or another branch.
+
 ## Examples
 
 Beside the examples below, you may want to check the [documentation](https://nlohmann.github.io/json/) where each function contains a separate code example (e.g., check out [`emplace()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5338e282d1d02bed389d852dd670d98d.html#a5338e282d1d02bed389d852dd670d98d)). All [example files](https://github.com/nlohmann/json/tree/develop/doc/examples) can be compiled and executed on their own (e.g., file [emplace.cpp](https://github.com/nlohmann/json/blob/develop/doc/examples/emplace.cpp)).
@@ -242,7 +301,7 @@ json j2 = {
 };
 ```
 
-Note that in all these cases, you never need to "tell" the compiler which JSON value type you want to use. If you want to be explicit or express some edge cases, the functions [`json::array`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_aa80485befaffcadaa39965494e0b4d2e.html#aa80485befaffcadaa39965494e0b4d2e) and [`json::object`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_aa13f7c0615867542ce80337cbcf13ada.html#aa13f7c0615867542ce80337cbcf13ada) will help:
+Note that in all these cases, you never need to "tell" the compiler which JSON value type you want to use. If you want to be explicit or express some edge cases, the functions [`json::array()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9ad7ec0bc1082ed09d10900fbb20a21f.html#a9ad7ec0bc1082ed09d10900fbb20a21f) and [`json::object()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf509a7c029100d292187068f61c99b8.html#aaf509a7c029100d292187068f61c99b8) will help:
 
 ```cpp
 // a way to express the empty array []
@@ -277,7 +336,7 @@ auto j2 = R"(
 
 Note that without appending the `_json` suffix, the passed string literal is not parsed, but just used as JSON string value. That is, `json j = "{ \"happy\": true, \"pi\": 3.141 }"` would just store the string `"{ "happy": true, "pi": 3.141 }"` rather than parsing the actual object.
 
-The above example can also be expressed explicitly using [`json::parse()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5a0339361f3282cb8fd2f9ede6e17d72.html#a5a0339361f3282cb8fd2f9ede6e17d72):
+The above example can also be expressed explicitly using [`json::parse()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a265a473e939184aa42655c9ccdf34e58.html#a265a473e939184aa42655c9ccdf34e58):
 
 ```cpp
 // parse explicitly
@@ -288,7 +347,7 @@ You can also get a string representation of a JSON value (serialize):
 
 ```cpp
 // explicit conversion to string
-std::string s = j.dump();    // {\"happy\":true,\"pi\":3.141}
+std::string s = j.dump();    // {"happy":true,"pi":3.141}
 
 // serialization with pretty printing
 // pass in the amount of spaces to indent
@@ -320,7 +379,7 @@ std::cout << cpp_string << " == " << cpp_string2 << " == " << j_string.get<std::
 std::cout << j_string << " == " << serialized_string << std::endl;
 ```
 
-[`.dump()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a50ec80b02d0f3f51130d4abb5d1cfdc5.html#a50ec80b02d0f3f51130d4abb5d1cfdc5) always returns the serialized value, and [`.get<std::string>()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a16f9445f7629f634221a42b967cdcd43.html#a16f9445f7629f634221a42b967cdcd43) returns the originally stored string value.
+[`.dump()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a50ec80b02d0f3f51130d4abb5d1cfdc5.html#a50ec80b02d0f3f51130d4abb5d1cfdc5) always returns the serialized value, and [`.get<std::string>()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_aa6602bb24022183ab989439e19345d08.html#aa6602bb24022183ab989439e19345d08) returns the originally stored string value.
 
 Note the library only supports UTF-8. When you store strings with different encodings in the library, calling [`dump()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a50ec80b02d0f3f51130d4abb5d1cfdc5.html#a50ec80b02d0f3f51130d4abb5d1cfdc5) may throw an exception unless `json::error_handler_t::replace` or `json::error_handler_t::ignore` are used as error handlers.
 
@@ -357,7 +416,7 @@ 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 content is stored as contiguous byte sequence, for instance a `std::vector<std::uint8_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'};
@@ -371,6 +430,53 @@ std::vector<std::uint8_t> v = {'t', 'r', 'u', 'e'};
 json j = json::parse(v);
 ```
 
+#### Custom data source
+
+Since the parse function accepts arbitrary iterator ranges, you can provide your own data sources by implementing the `LegacyInputIterator` concept.
+
+```cpp
+struct MyContainer {
+  void advance();
+  const char& get_current();
+};
+
+struct MyIterator {
+    using difference_type = std::ptrdiff_t;
+    using value_type = char;
+    using pointer = const char*;
+    using reference = const char&;
+    using iterator_category = std::input_iterator_tag;
+
+    MyIterator& operator++() {
+        MyContainer.advance();
+        return *this;
+    }
+
+    bool operator!=(const MyIterator& rhs) const {
+        return rhs.target != target;
+    }
+
+    reference operator*() const {
+        return target.get_current();
+    }
+
+    MyContainer* target = nullptr;
+};
+
+MyIterator begin(MyContainer& tgt) {
+    return MyIterator{&tgt};
+}
+
+MyIterator end(const MyContainer&) {
+    return {}; 
+}
+
+void foo() {
+    MyContainer c;
+    json j = json::parse(c);
+}
+```
+
 #### SAX interface
 
 The library uses a SAX-like interface with the following functions:
@@ -444,7 +550,7 @@ j[1] = 42;
 bool foo = j.at(2);
 
 // comparison
-j == "[\"foo\", 1, true]"_json;  // true
+j == "[\"foo\", 42, true]"_json;  // true
 
 // other stuff
 j.size();     // 3 entries
@@ -485,6 +591,11 @@ for (auto& [key, value] : o.items()) {
 }
 
 // find an entry
+if (o.contains("foo")) {
+  // there is an entry with key "foo"
+}
+
+// or via find and an iterator
 if (o.find("foo") != o.end()) {
   // there is an entry with key "foo"
 }
@@ -924,7 +1035,7 @@ NLOHMANN_JSON_SERIALIZE_ENUM( TaskState, {
 })
 ```
 
-The `NLOHMANN_JSON_SERIALIZE_ENUM()` macro declares a set of `to_json()` / `from_json()` functions for type `TaskState` while avoiding repetition and boilerplate serilization code.
+The `NLOHMANN_JSON_SERIALIZE_ENUM()` macro declares a set of `to_json()` / `from_json()` functions for type `TaskState` while avoiding repetition and boilerplate serialization code.
 
 **Usage:**
 
@@ -952,7 +1063,7 @@ Other Important points:
 
 ### Binary formats (BSON, CBOR, MessagePack, and UBJSON)
 
-Though JSON is a ubiquitous data format, it is not a very compact format suitable for data exchange, for instance over a network. Hence, the library supports [BSON](http://bsonspec.org) (Binary JSON), [CBOR](http://cbor.io) (Concise Binary Object Representation), [MessagePack](http://msgpack.org), and [UBJSON](http://ubjson.org) (Universal Binary JSON Specification) to efficiently encode JSON values to byte vectors and to decode such vectors.
+Though JSON is a ubiquitous data format, it is not a very compact format suitable for data exchange, for instance over a network. Hence, the library supports [BSON](http://bsonspec.org) (Binary JSON), [CBOR](https://cbor.io) (Concise Binary Object Representation), [MessagePack](https://msgpack.org), and [UBJSON](http://ubjson.org) (Universal Binary JSON Specification) to efficiently encode JSON values to byte vectors and to decode such vectors.
 
 ```cpp
 // create a JSON value
@@ -991,16 +1102,47 @@ std::vector<std::uint8_t> v_ubjson = json::to_ubjson(j);
 json j_from_ubjson = json::from_ubjson(v_ubjson);
 ```
 
+The library also supports binary types from BSON, CBOR (byte strings), and MessagePack (bin, ext, fixext). They are stored by default as `std::vector<std::uint8_t>` to be processed outside of the library.
+
+```cpp
+// CBOR byte string with payload 0xCAFE
+std::vector<std::uint8_t> v = {0x42, 0xCA, 0xFE};
+
+// read value
+json j = json::from_cbor(v);
+
+// the JSON value has type binary
+j.is_binary(); // true
+
+// get reference to stored binary value
+auto& binary = j.get_binary();
+
+// the binary value has no subtype (CBOR has no binary subtypes)
+binary.has_subtype(); // false
+
+// access std::vector<std::uint8_t> member functions
+binary.size(); // 2
+binary[0]; // 0xCA
+binary[1]; // 0xFE
+
+// set subtype to 0x10
+binary.set_subtype(0x10);
+
+// serialize to MessagePack
+auto cbor = json::to_msgpack(j); // 0xD5 (fixext2), 0x10, 0xCA, 0xFE
+```
+
 
 ## Supported compilers
 
-Though it's 2019 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
+Though it's 2020 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
 
-- GCC 4.8 - 9.0 (and possibly later)
-- Clang 3.4 - 8.0 (and possibly later)
+- GCC 4.8 - 10.1 (and possibly later)
+- Clang 3.4 - 10.0 (and possibly later)
 - Intel C++ Compiler 17.0.2 (and possibly later)
 - Microsoft Visual C++ 2015 / Build Tools 14.0.25123.0 (and possibly later)
 - Microsoft Visual C++ 2017 / Build Tools 15.5.180.51428 (and possibly later)
+- Microsoft Visual C++ 2019 / Build Tools 16.3.1+1def00d3d (and possibly later)
 
 I would be happy to learn about other compilers/versions.
 
@@ -1017,39 +1159,46 @@ 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`) 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](http://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.
 
-The following compilers are currently used in continuous integration at [Travis](https://travis-ci.org/nlohmann/json) and [AppVeyor](https://ci.appveyor.com/project/nlohmann/json):
+The following compilers are currently used in continuous integration at [Travis](https://travis-ci.org/nlohmann/json), [AppVeyor](https://ci.appveyor.com/project/nlohmann/json), [GitHub Actions](https://github.com/nlohmann/json/actions), and [CircleCI](https://circleci.com/gh/nlohmann/json):
 
-| Compiler        | Operating System             | Version String |
-|-----------------|------------------------------|----------------|
-| GCC 4.8.5       | Ubuntu 14.04.5 LTS           | g++-4.8 (Ubuntu 4.8.5-2ubuntu1~14.04.2) 4.8.5 |
-| GCC 4.9.4       | Ubuntu 14.04.1 LTS           | g++-4.9 (Ubuntu 4.9.4-2ubuntu1~14.04.1) 4.9.4 |
-| GCC 5.5.0       | Ubuntu 14.04.1 LTS           | g++-5 (Ubuntu 5.5.0-12ubuntu1~14.04) 5.5.0 20171010 |
-| GCC 6.4.0       | Ubuntu 14.04.1 LTS           | g++-6 (Ubuntu 6.4.0-17ubuntu1~14.04) 6.4.0 20180424 |
-| GCC 7.3.0       | Ubuntu 14.04.1 LTS           | g++-7 (Ubuntu 7.3.0-21ubuntu1~14.04) 7.3.0 |
-| GCC 7.3.0       | Windows Server 2012 R2 (x64) | g++ (x86_64-posix-seh-rev0, Built by MinGW-W64 project) 7.3.0 |
-| GCC 8.1.0       | Ubuntu 14.04.1 LTS           | g++-8 (Ubuntu 8.1.0-5ubuntu1~14.04) 8.1.0 |
-| Clang 3.5.0     | Ubuntu 14.04.1 LTS           | clang version 3.5.0-4ubuntu2~trusty2 (tags/RELEASE_350/final) (based on LLVM 3.5.0) |
-| Clang 3.6.2     | Ubuntu 14.04.1 LTS           | clang version 3.6.2-svn240577-1~exp1 (branches/release_36) (based on LLVM 3.6.2) |
-| Clang 3.7.1     | Ubuntu 14.04.1 LTS           | clang version 3.7.1-svn253571-1~exp1 (branches/release_37) (based on LLVM 3.7.1) |
-| Clang 3.8.0     | Ubuntu 14.04.1 LTS           | clang version 3.8.0-2ubuntu3~trusty5 (tags/RELEASE_380/final) |
-| Clang 3.9.1     | Ubuntu 14.04.1 LTS           | clang version 3.9.1-4ubuntu3~14.04.3 (tags/RELEASE_391/rc2) |
-| Clang 4.0.1     | Ubuntu 14.04.1 LTS           | clang version 4.0.1-svn305264-1~exp1 (branches/release_40) |
-| Clang 5.0.2     | Ubuntu 14.04.1 LTS           | clang version 5.0.2-svn328729-1~exp1~20180509123505.100 (branches/release_50) |
-| Clang 6.0.1     | Ubuntu 14.04.1 LTS           | clang version 6.0.1-svn334776-1~exp1~20180726133705.85 (branches/release_60) |
-| Clang 7.0.1     | Ubuntu 14.04.1 LTS           | clang version 7.0.1-svn348686-1~exp1~20181213084532.54 (branches/release_70) |
-| Clang Xcode 8.3 | OSX 10.11.6 | Apple LLVM version 8.1.0 (clang-802.0.38) |
-| Clang Xcode 9.0 | OSX 10.12.6 | Apple LLVM version 9.0.0 (clang-900.0.37) |
-| Clang Xcode 9.1 | OSX 10.12.6 | Apple LLVM version 9.0.0 (clang-900.0.38) |
-| Clang Xcode 9.2 | OSX 10.13.3 | Apple LLVM version 9.1.0 (clang-902.0.39.1) |
-| Clang Xcode 9.3 | OSX 10.13.3 | Apple LLVM version 9.1.0 (clang-902.0.39.2) |
-| Clang Xcode 10.0 | OSX 10.13.3 | Apple LLVM version 10.0.0 (clang-1000.11.45.2) |
-| Clang Xcode 10.1 | OSX 10.13.3 | Apple LLVM version 10.0.0 (clang-1000.11.45.5) |
-| Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25420.1, MSVC 19.0.24215.1 |
-| Visual Studio 2017 | Windows Server 2016 | Microsoft (R) Build Engine version 15.7.180.61344, MSVC 19.14.26433.0 |
+| Compiler                                                        | Operating System   | CI Provider    |
+|-----------------------------------------------------------------|--------------------|----------------|
+| Apple Clang 9.1.0 (clang-902.0.39.1); Xcode 9.3                 | macOS 10.13.3      | Travis         |
+| Apple Clang 9.1.0 (clang-902.0.39.2); Xcode 9.4.1               | macOS 10.13.6      | Travis         |
+| Apple Clang 10.0.0 (clang-1000.11.45.2); Xcode 10.0             | macOS 10.13.6      | Travis         |
+| Apple Clang 10.0.0 (clang-1000.11.45.5); Xcode 10.1             | macOS 10.13.6      | Travis         |
+| Apple Clang 10.0.1 (clang-1001.0.46.4); Xcode 10.2.1            | macOS 10.14.4      | Travis         |
+| Apple Clang 11.0.0 (clang-1100.0.33.12); Xcode 11.2.1           | macOS 10.14.6      | Travis         |
+| Apple Clang 11.0.3 (clang-1103.0.32.59); Xcode 11.4.1           | macOS 10.15.4      | GitHub Actions |
+| Clang 3.5.0 (3.5.0-4ubuntu2~trusty2)                            | Ubuntu 14.04.5 LTS | Travis         |
+| Clang 3.6.2 (3.6.2-svn240577-1~exp1)                            | Ubuntu 14.04.5 LTS | Travis         |
+| Clang 3.7.1 (3.7.1-svn253571-1~exp1)                            | Ubuntu 14.04.5 LTS | Travis         |
+| Clang 3.8.0 (3.8.0-2ubuntu3~trusty5)                            | Ubuntu 14.04.5 LTS | Travis         |
+| Clang 3.9.1 (3.9.1-4ubuntu3~14.04.3)                            | Ubuntu 14.04.5 LTS | Travis         |
+| Clang 4.0.1 (4.0.1-svn305264-1~exp1)                            | Ubuntu 14.04.5 LTS | Travis         |
+| Clang 5.0.2 (version 5.0.2-svn328729-1~exp1~20180509123505.100) | Ubuntu 14.04.5 LTS | Travis         |
+| Clang 6.0.1 (6.0.1-svn334776-1~exp1~20190309042707.121)         | Ubuntu 14.04.5 LTS | Travis         |
+| Clang 7.1.0 (7.1.0-svn353565-1~exp1~20190419134007.64)          | Ubuntu 14.04.5 LTS | Travis         |
+| Clang 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)                       | Ubuntu 18.04.4 LTS | Travis         |
+| GCC 4.8.5 (Ubuntu 4.8.5-4ubuntu8~14.04.2)                       | Ubuntu 14.04.5 LTS | Travis         |
+| GCC 4.9.4 (Ubuntu 4.9.4-2ubuntu1~14.04.1)                       | Ubuntu 14.04.5 LTS | Travis         |
+| GCC 5.5.0 (Ubuntu 5.5.0-12ubuntu1~14.04)                        | Ubuntu 14.04.5 LTS | Travis         |
+| GCC 6.3.0 (Debian 6.3.0-18+deb9u1)                              | Debian 9           | Circle CI      |
+| GCC 6.5.0 (Ubuntu 6.5.0-2ubuntu1~14.04.1)                       | Ubuntu 14.04.5 LTS | Travis         |
+| GCC 7.3.0 (x86_64-posix-seh-rev0, Built by MinGW-W64 project)   | Windows-6.3.9600   | AppVeyor       |
+| GCC 7.5.0 (Ubuntu 7.5.0-3ubuntu1~14.04.1)                       | Ubuntu 14.04.5 LTS | Travis         |
+| GCC 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)                         | Ubuntu 18.04.4 LTS | GitHub Actions |
+| GCC 8.4.0 (Ubuntu 8.4.0-1ubuntu1~14.04)                         | Ubuntu 14.04.5 LTS | Travis         |
+| GCC 9.3.0 (Ubuntu 9.3.0-11ubuntu0~14.04)                        | Ubuntu 14.04.5 LTS | Travis         |
+| GCC 10.1.0 (Arch Linux latest)                                  | Arch Linux         | Circle CI      |
+| MSVC 19.0.24241.7 (Build Engine version 14.0.25420.1)           | Windows-6.3.9600   | AppVeyor       |
+| MSVC 19.16.27035.0 (15.9.21+g9802d43bc3 for .NET Framework)     | Windows-10.0.14393 | AppVeyor       |
+| MSVC 19.25.28614.0 (Build Engine version 16.5.0+d4cbfca49 for .NET Framework) | Windows-10.0.17763  | AppVeyor       |
+| MSVC 19.25.28614.0 (Build Engine version 16.5.0+d4cbfca49 for .NET Framework) | Windows-10.0.17763  | GitHub Actions |
 
 ## License
 
@@ -1067,13 +1216,15 @@ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR I
 
 * * *
 
-The class contains the UTF-8 Decoder from Bjoern Hoehrmann which is licensed under the [MIT License](http://opensource.org/licenses/MIT) (see above). Copyright &copy; 2008-2009 [Björn Hoehrmann](http://bjoern.hoehrmann.de/) <bjoern@hoehrmann.de>
+The class contains the UTF-8 Decoder from Bjoern Hoehrmann which is licensed under the [MIT License](http://opensource.org/licenses/MIT) (see above). Copyright &copy; 2008-2009 [Björn Hoehrmann](https://bjoern.hoehrmann.de/) <bjoern@hoehrmann.de>
 
-The class contains a slightly modified version of the Grisu2 algorithm from Florian Loitsch which is licensed under the [MIT License](http://opensource.org/licenses/MIT) (see above). Copyright &copy; 2009 [Florian Loitsch](http://florian.loitsch.com/)
+The class contains a slightly modified version of the Grisu2 algorithm from Florian Loitsch which is licensed under the [MIT License](http://opensource.org/licenses/MIT) (see above). Copyright &copy; 2009 [Florian Loitsch](https://florian.loitsch.com/)
+
+The class contains a copy of [Hedley](https://nemequ.github.io/hedley/) from Evan Nemerson which is licensed as [CC0-1.0](https://creativecommons.org/publicdomain/zero/1.0/).
 
 ## Contact
 
-If you have questions regarding the library, I would like to invite you to [open an issue at GitHub](https://github.com/nlohmann/json/issues/new). Please describe your request, problem, or question as detailed as possible, and also mention the version of the library you are using as well as the version of your compiler and operating system. Opening an issue at GitHub allows other users and contributors to this library to collaborate. For instance, I have little experience with MSVC, and most issues in this regard have been solved by a growing community. If you have a look at the [closed issues](https://github.com/nlohmann/json/issues?q=is%3Aissue+is%3Aclosed), you will see that we react quite timely in most cases.
+If you have questions regarding the library, I would like to invite you to [open an issue at GitHub](https://github.com/nlohmann/json/issues/new/choose). Please describe your request, problem, or question as detailed as possible, and also mention the version of the library you are using as well as the version of your compiler and operating system. Opening an issue at GitHub allows other users and contributors to this library to collaborate. For instance, I have little experience with MSVC, and most issues in this regard have been solved by a growing community. If you have a look at the [closed issues](https://github.com/nlohmann/json/issues?q=is%3Aissue+is%3Aclosed), you will see that we react quite timely in most cases.
 
 Only if your request would contain confidential information, please [send me an email](mailto:mail@nlohmann.me). For encrypted messages, please use [this key](https://keybase.io/nlohmann/pgp_keys.asc).
 
@@ -1126,7 +1277,7 @@ I deeply appreciate the help of the following people.
 - [Mário Feroldi](https://github.com/thelostt) fixed a small typo.
 - [duncanwerner](https://github.com/duncanwerner) found a really embarrassing performance regression in the 2.0.0 release.
 - [Damien](https://github.com/dtoma) fixed one of the last conversion warnings.
-- [Thomas Braun](https://github.com/t-b) fixed a warning in a test case.
+- [Thomas Braun](https://github.com/t-b) fixed a warning in a test case and adjusted MSVC calls in the CI.
 - [Théo DELRIEU](https://github.com/theodelrieu) patiently and constructively oversaw the long way toward [iterator-range parsing](https://github.com/nlohmann/json/issues/290). He also implemented the magic behind the serialization/deserialization of user-defined types and split the single header file into smaller chunks.
 - [Stefan](https://github.com/5tefan) fixed a minor issue in the documentation.
 - [Vasil Dimov](https://github.com/vasild) fixed the documentation regarding conversions from `std::multiset`.
@@ -1242,7 +1393,7 @@ I deeply appreciate the help of the following people.
 - [Ivor Wanders](https://github.com/iwanders) helped reducing the CMake requirement to version 3.1.
 - [njlr](https://github.com/njlr) updated the Buckaroo instructions.
 - [Lion](https://github.com/lieff) fixed a compilation issue with GCC 7 on CentOS.
-- [Isaac Nickaein](https://github.com/nickaein) improved the integer serilization performance and  implemented the `contains()` function.
+- [Isaac Nickaein](https://github.com/nickaein) improved the integer serialization performance and  implemented the `contains()` function.
 - [past-due](https://github.com/past-due) suppressed an unfixable warning.
 - [Elvis Oric](https://github.com/elvisoric) improved Meson support.
 - [Matěj Plch](https://github.com/Afforix) fixed an example in the README.
@@ -1254,6 +1405,53 @@ I deeply appreciate the help of the following people.
 - [Hani](https://github.com/hnkb) documented how to install the library with NuGet.
 - [Mark Beckwith](https://github.com/wythe) fixed a typo.
 - [yann-morin-1998](https://github.com/yann-morin-1998) helped reducing the CMake requirement to version 3.1.
+- [Konstantin Podsvirov](https://github.com/podsvirov) maintains a package for the MSYS2 software distro.
+- [remyabel](https://github.com/remyabel) added GNUInstallDirs to the CMake files.
+- [Taylor Howard](https://github.com/taylorhoward92) fixed a unit test.
+- [Gabe Ron](https://github.com/Macr0Nerd) implemented the `to_string` method.
+- [Watal M. Iwasaki](https://github.com/heavywatal) fixed a Clang warning.
+- [Viktor Kirilov](https://github.com/onqtam) switched the unit tests from [Catch](https://github.com/philsquared/Catch) to [doctest](https://github.com/onqtam/doctest)
+- [Juncheng E](https://github.com/ejcjason) fixed a typo.
+- [tete17](https://github.com/tete17) fixed a bug in the `contains` function.
+- [Xav83](https://github.com/Xav83) fixed some cppcheck warnings.
+- [0xflotus](https://github.com/0xflotus) fixed some typos.
+- [Christian Deneke](https://github.com/chris0x44) added a const version of `json_pointer::back`.
+- [Julien Hamaide](https://github.com/crazyjul) made the `items()` function work with custom string types.
+- [Evan Nemerson](https://github.com/nemequ) updated fixed a bug in Hedley and updated this library accordingly.
+- [Florian Pigorsch](https://github.com/flopp) fixed a lot of typos.
+- [Camille Bégué](https://github.com/cbegue) fixed an issue in the conversion from  `std::pair` and `std::tuple` to `json`.
+- [Anthony VH](https://github.com/AnthonyVH) fixed a compile error in an enum deserialization.
+- [Yuriy Vountesmery](https://github.com/ua-code-dragon) noted a subtle bug in a preprocessor check.
+- [Chen](https://github.com/dota17) fixed numerous issues in the library.
+- [Antony Kellermann](https://github.com/aokellermann) added a CI step for GCC 10.1.
+- [Alex](https://github.com/gistrec) fixed an MSVC warning.
+- [Rainer](https://github.com/rvjr) proposed an improvement in the floating-point serialization in CBOR.
+- [Francois Chabot](https://github.com/FrancoisChabot) made performance improvements in the input adapters.
+- [Arthur Sonzogni](https://github.com/ArthurSonzogni) documented how the library can be included via `FetchContent`.
+- [Rimas Misevičius](https://github.com/rmisev) fixed an error message.
+- [Alexander Myasnikov](https://github.com/alexandermyasnikov) fixed some examples and a link in the README.
+- [Hubert Chathi](https://github.com/uhoreg) made CMake's version config file architecture-independent.
+- [OmnipotentEntity](https://github.com/OmnipotentEntity) implemented the binary values for CBOR, MessagePack, BSON, and UBJSON.
+- [ArtemSarmini](https://github.com/ArtemSarmini) fixed a compilation issue with GCC 10 and fixed a leak.
+- [Evgenii Sopov](https://github.com/sea-kg) integrated the library to the wsjcpp package manager.
+- [Sergey Linev](https://github.com/linev) fixed a compiler warning.
+- [Miguel Magalhães](https://github.com/magamig) fixed the year in the copyright.
+- [Gareth Sylvester-Bradley](https://github.com/garethsb-sony) fixed a compilation issue with MSVC.
+- [Alexander “weej” Jones](https://github.com/alex-weej) fixed an example in the README.
+- [Antoine Cœur](https://github.com/Coeur) fixed some typos in the documentation.
+- [jothepro](https://github.com/jothepro) updated links to the Hunter package.
+- [Dave Lee](https://github.com/kastiglione) fixed link in the README.
+- [Joël Lamotte](https://github.com/Klaim) added instruction for using Build2's package manager.
+- [Paul Jurczak](https://github.com/pauljurczak) fixed an example in the README.
+- [Sonu Lohani](https://github.com/sonulohani) fixed a warning.
+- [Carlos Gomes Martinho](https://github.com/gocarlos) updated the Conan package source.
+- [Konstantin Podsvirov](https://github.com/podsvirov) fixed the MSYS2 package documentation.
+- [Tridacnid](https://github.com/Tridacnid) improved the CMake tests.
+- [Michael](https://github.com/MBalszun) fixed MSVC warnings.
+- [Quentin Barbarat](https://github.com/quentin-dev) fixed an example in the documentation.
+- [XyFreak](https://github.com/XyFreak) fixed a compiler warning.
+- [TotalCaesar659](https://github.com/TotalCaesar659) fixed links in the README.
+- [Tanuj Garg](https://github.com/tanuj208) improved the fuzzer coverage for UBSAN input.
 
 Thanks a lot for helping out! Please [let me know](mailto:mail@nlohmann.me) if I forgot someone.
 
@@ -1263,27 +1461,30 @@ Thanks a lot for helping out! Please [let me know](mailto:mail@nlohmann.me) if I
 The library itself consists of a single header file licensed under the MIT license. However, it is built, tested, documented, and whatnot using a lot of third-party tools and services. Thanks a lot!
 
 - [**amalgamate.py - Amalgamate C source and header files**](https://github.com/edlund/amalgamate) to create a single header file
-- [**American fuzzy lop**](http://lcamtuf.coredump.cx/afl/) for fuzz testing
+- [**American fuzzy lop**](https://lcamtuf.coredump.cx/afl/) for fuzz testing
 - [**AppVeyor**](https://www.appveyor.com) for [continuous integration](https://ci.appveyor.com/project/nlohmann/json) on Windows
-- [**Artistic Style**](http://astyle.sourceforge.net) for automatic source code identation
-- [**Catch**](https://github.com/philsquared/Catch) for the unit tests
-- [**Clang**](http://clang.llvm.org) for compilation with code sanitizers
+- [**Artistic Style**](http://astyle.sourceforge.net) for automatic source code indentation
+- [**CircleCI**](https://circleci.com) for [continuous integration](https://circleci.com/gh/nlohmann/json).
+- [**Clang**](https://clang.llvm.org) for compilation with code sanitizers
 - [**CMake**](https://cmake.org) for build automation
 - [**Codacity**](https://www.codacy.com) for further [code analysis](https://www.codacy.com/app/nlohmann/json)
 - [**Coveralls**](https://coveralls.io) to measure [code coverage](https://coveralls.io/github/nlohmann/json)
 - [**Coverity Scan**](https://scan.coverity.com) for [static analysis](https://scan.coverity.com/projects/nlohmann-json)
 - [**cppcheck**](http://cppcheck.sourceforge.net) for static analysis
-- [**Doxygen**](http://www.stack.nl/~dimitri/doxygen/) to generate [documentation](https://nlohmann.github.io/json/)
+- [**doctest**](https://github.com/onqtam/doctest) for the unit tests
+- [**Doxygen**](https://www.doxygen.nl/index.html) to generate [documentation](https://nlohmann.github.io/json/doxygen/index.html)
 - [**git-update-ghpages**](https://github.com/rstacruz/git-update-ghpages) to upload the documentation to gh-pages
 - [**GitHub Changelog Generator**](https://github.com/skywinder/github-changelog-generator) to generate the [ChangeLog](https://github.com/nlohmann/json/blob/develop/ChangeLog.md)
 - [**Google Benchmark**](https://github.com/google/benchmark) to implement the benchmarks
-- [**libFuzzer**](http://llvm.org/docs/LibFuzzer.html) to implement fuzz testing for OSS-Fuzz
+- [**Hedley**](https://nemequ.github.io/hedley/) to avoid re-inventing several compiler-agnostic feature macros
+- [**lcov**](http://ltp.sourceforge.net/coverage/lcov.php) to process coverage information and create a HTML view
+- [**libFuzzer**](https://llvm.org/docs/LibFuzzer.html) to implement fuzz testing for OSS-Fuzz
 - [**OSS-Fuzz**](https://github.com/google/oss-fuzz) for continuous fuzz testing of the library ([project repository](https://github.com/google/oss-fuzz/tree/master/projects/json))
 - [**Probot**](https://probot.github.io) for automating maintainer tasks such as closing stale issues, requesting missing information, or detecting toxic comments.
 - [**send_to_wandbox**](https://github.com/nlohmann/json/blob/develop/doc/scripts/send_to_wandbox.py) to send code examples to [Wandbox](http://melpon.org/wandbox)
 - [**Travis**](https://travis-ci.org) for [continuous integration](https://travis-ci.org/nlohmann/json) on Linux and macOS
-- [**Valgrind**](http://valgrind.org) to check for correct memory management
-- [**Wandbox**](http://melpon.org/wandbox) for [online examples](https://wandbox.org/permlink/TarF5pPn9NtHQjhf)
+- [**Valgrind**](https://valgrind.org) to check for correct memory management
+- [**Wandbox**](https://wandbox.org) for [online examples](https://wandbox.org/permlink/3lCHrFUZANONKv7a)
 
 
 ## Projects using JSON for Modern C++
@@ -1293,18 +1494,56 @@ The library is currently used in Apple macOS Sierra and iOS 10. I am not sure wh
 
 ## Notes
 
-- The code contains numerous debug **assertions** which can be switched off by defining the preprocessor macro `NDEBUG`, see the [documentation of `assert`](https://en.cppreference.com/w/cpp/error/assert). In particular, note [`operator[]`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a233b02b0839ef798942dd46157cc0fe6.html#a233b02b0839ef798942dd46157cc0fe6) implements **unchecked access** for const objects: If the given key is not present, the behavior is undefined (think of a dereferenced null pointer) and yields an [assertion failure](https://github.com/nlohmann/json/issues/289) if assertions are switched on. If you are not sure whether an element in an object exists, use checked access with the [`at()` function](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a73ae333487310e3302135189ce8ff5d8.html#a73ae333487310e3302135189ce8ff5d8).
-- As the exact type of a number is not defined in the [JSON specification](https://tools.ietf.org/html/rfc7159.html), this library tries to choose the best fitting C++ number type automatically. As a result, the type `double` may be used to store numbers which may yield [**floating-point exceptions**](https://github.com/nlohmann/json/issues/181) in certain rare situations if floating-point exceptions have been unmasked in the calling code. These exceptions are not caused by the library and need to be fixed in the calling code, such as by re-masking the exceptions prior to calling library functions.
-- The library supports **Unicode input** as follows:
-  - Only **UTF-8** encoded input is supported which is the default encoding for JSON according to [RFC 7159](https://tools.ietf.org/html/rfc7159.html#section-8.1).
-  - Other encodings such as Latin-1, UTF-16, or UTF-32 are not supported and will yield parse or serialization errors.
-  - [Unicode noncharacters](http://www.unicode.org/faq/private_use.html#nonchar1) will not be replaced by the library.
-  - Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
-  - The strings stored in the library are UTF-8 encoded. When using the default string type (`std::string`), note that its length/size functions return the number of stored bytes rather than the number of characters or glyphs.
-- The code can be compiled without C++ **runtime type identification** features; that is, you can use the `-fno-rtti` compiler flag.
-- **Exceptions** are used widely within the library. They can, however, be switched off with either using the compiler flag `-fno-exceptions` or by defining the symbol `JSON_NOEXCEPTION`. In this case, exceptions are replaced by an `abort()` call.
-- By default, the library does not preserve the **insertion order of object elements**. This is standards-compliant, as the [JSON standard](https://tools.ietf.org/html/rfc7159.html) defines objects as "an unordered collection of zero or more name/value pairs". If you do want to preserve the insertion order, you can specialize the object type with containers like [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) ([integration](https://github.com/nlohmann/json/issues/546#issuecomment-304447518)) or [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).
+### Character encoding
 
+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).
+- `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.
+- Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
+- The strings stored in the library are UTF-8 encoded. When using the default string type (`std::string`), note that its length/size functions return the number of stored bytes rather than the number of characters or glyphs.
+- When you store strings with different encodings in the library, calling [`dump()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a50ec80b02d0f3f51130d4abb5d1cfdc5.html#a50ec80b02d0f3f51130d4abb5d1cfdc5) may throw an exception unless `json::error_handler_t::replace` or `json::error_handler_t::ignore` are used as error handlers.
+
+### Comments in JSON
+
+This library does not support comments. 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:
+
+	> 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. 
+
+	> Suppose you are using JSON to keep configuration files, which you would like to annotate. Go ahead and insert all the comments you like. Then pipe it through JSMin before handing it to your JSON parser.
+
+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.
+
+This library will not support comments in the future. If you wish to use comments, I see three options:
+
+1. Strip comments before using this library.
+2. Use a different JSON library with comment support.
+3. Use a format that natively supports comments (e.g., YAML or JSON5).
+
+### Order of object keys
+
+By default, the library does not preserve the **insertion order of object elements**. This is standards-compliant, as the [JSON standard](https://tools.ietf.org/html/rfc8259.html) defines objects as "an unordered collection of zero or more name/value pairs". If you do want to preserve the insertion order, you can specialize the object type with containers like [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) ([integration](https://github.com/nlohmann/json/issues/546#issuecomment-304447518)) or [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).
+
+### Memory Release
+
+We checked with Valgrind and the Address Sanitizer (ASAN) that there are no memory leaks. 
+
+If you find that a parsing program with this library does not release memory, please consider the following case and it maybe unrelated to this library. 
+
+**Your program is compiled with glibc.** There is a tunable threshold that glibc uses to decide whether to actually return memory to the system or whether to cache it for later reuse. If in your program you make lots of small allocations and those small allocations are not a contiguous block and are presumably below the threshold, then they will not get returned to the OS.
+Here is a related issue [#1924](https://github.com/nlohmann/json/issues/1924).
+
+### Further notes
+
+- The code contains numerous debug **assertions** which can be switched off by defining the preprocessor macro `NDEBUG`, see the [documentation of `assert`](https://en.cppreference.com/w/cpp/error/assert). In particular, note [`operator[]`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a233b02b0839ef798942dd46157cc0fe6.html#a233b02b0839ef798942dd46157cc0fe6) implements **unchecked access** for const objects: If the given key is not present, the behavior is undefined (think of a dereferenced null pointer) and yields an [assertion failure](https://github.com/nlohmann/json/issues/289) if assertions are switched on. If you are not sure whether an element in an object exists, use checked access with the [`at()` function](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a73ae333487310e3302135189ce8ff5d8.html#a73ae333487310e3302135189ce8ff5d8).
+- As the exact type of a number is not defined in the [JSON specification](https://tools.ietf.org/html/rfc8259.html), this library tries to choose the best fitting C++ number type automatically. As a result, the type `double` may be used to store numbers which may yield [**floating-point exceptions**](https://github.com/nlohmann/json/issues/181) in certain rare situations if floating-point exceptions have been unmasked in the calling code. These exceptions are not caused by the library and need to be fixed in the calling code, such as by re-masking the exceptions prior to calling library functions.
+- The code can be compiled without C++ **runtime type identification** features; that is, you can use the `-fno-rtti` compiler flag.
+- **Exceptions** are used widely within the library. They can, however, be switched off with either using the compiler flag `-fno-exceptions` or by defining the symbol `JSON_NOEXCEPTION`. In this case, exceptions are replaced by `abort()` calls. You can further control this behavior by defining `JSON_THROW_USER´` (overriding `throw`), `JSON_TRY_USER` (overriding `try`), and `JSON_CATCH_USER` (overriding `catch`). Note that `JSON_THROW_USER` should leave the current scope (e.g., by throwing or aborting), as continuing after it may yield undefined behavior.
 
 ## Execute unit tests
 
@@ -1313,7 +1552,7 @@ To compile and run the tests, you need to execute
 ```sh
 $ mkdir build
 $ cd build
-$ cmake ..
+$ cmake .. -DJSON_BuildTests=On
 $ cmake --build .
 $ ctest --output-on-failure
 ```

appveyor.yml

@@ -3,6 +3,35 @@ version: '{build}'
 environment:
   matrix:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      configuration: Debug
+      platform: x86
+      CXX_FLAGS: ""
+      LINKER_FLAGS: ""
+      GENERATOR: Visual Studio 14 2015
+
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      configuration: Debug
+      platform: x86
+      CXX_FLAGS: ""
+      LINKER_FLAGS: ""
+      GENERATOR: Visual Studio 15 2017
+
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      configuration: Debug
+      platform: x86
+      CXX_FLAGS: ""
+      LINKER_FLAGS: ""
+      GENERATOR: Visual Studio 16 2019
+
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      configuration: Debug
+      platform: x64
+      CXX_FLAGS: ""
+      LINKER_FLAGS: ""
+      GENERATOR: Visual Studio 16 2019
+
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      configuration: Debug
       COMPILER: mingw
       platform: x86
       CXX_FLAGS: ""
@@ -10,57 +39,88 @@ environment:
       GENERATOR: Ninja
 
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      configuration: Release
+      COMPILER: mingw
+      platform: x86
+      CXX_FLAGS: ""
+      LINKER_FLAGS: ""
+      GENERATOR: Ninja
+
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      configuration: Release
       platform: x86
       CXX_FLAGS: ""
       LINKER_FLAGS: ""
       GENERATOR: Visual Studio 14 2015
 
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      configuration: Release
       platform: x86
+      name: with_win_header
       CXX_FLAGS: ""
       LINKER_FLAGS: ""
-      GENERATOR: Visual Studio 15 2017
+      GENERATOR: Visual Studio 14 2015
 
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      configuration: Release
       platform: x86
       CXX_FLAGS: "/permissive- /std:c++latest /utf-8"
       LINKER_FLAGS: ""
       GENERATOR: Visual Studio 15 2017
 
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      configuration: Release
+      platform: x86
+      CXX_FLAGS: ""
+      LINKER_FLAGS: ""
+      GENERATOR: Visual Studio 16 2019
+
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      configuration: Release
       platform: x64
       CXX_FLAGS: ""
       LINKER_FLAGS: ""
-      GENERATOR: Visual Studio 14 2015 Win64
+      GENERATOR: Visual Studio 14 2015
 
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      configuration: Release
       platform: x64
-      CXX_FLAGS: ""
-      LINKER_FLAGS: ""
-      GENERATOR: Visual Studio 15 2017 Win64
-
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      platform: x64
-      CXX_FLAGS: "/permissive- /std:c++latest /utf-8 /F4000000"
+      CXX_FLAGS: "/permissive- /std:c++latest /Zc:__cplusplus /utf-8 /F4000000"
       LINKER_FLAGS: "/STACK:4000000"
-      GENERATOR: Visual Studio 15 2017 Win64
+      GENERATOR: Visual Studio 15 2017
+
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      configuration: Release
+      platform: x64
+      CXX_FLAGS: ""
+      LINKER_FLAGS: ""
+      GENERATOR: Visual Studio 16 2019
 
 init:
   - cmake --version
   - msbuild /version
 
 install:
-  - if "%COMPILER%"=="mingw" appveyor DownloadFile https://github.com/ninja-build/ninja/releases/download/v1.6.0/ninja-win.zip -FileName ninja.zip
-  - if "%COMPILER%"=="mingw" 7z x ninja.zip -oC:\projects\deps\ninja > nul
-  - if "%COMPILER%"=="mingw" set PATH=C:\projects\deps\ninja;%PATH%
-  - if "%COMPILER%"=="mingw" set PATH=C:\mingw-w64\x86_64-7.3.0-posix-seh-rt_v5-rev0\mingw64\bin;%PATH%
-  - if "%COMPILER%"=="mingw" g++ --version
+  - if "%COMPILER%"=="mingw"  appveyor DownloadFile https://github.com/ninja-build/ninja/releases/download/v1.6.0/ninja-win.zip -FileName ninja.zip
+  - if "%COMPILER%"=="mingw"  7z x ninja.zip -oC:\projects\deps\ninja > nul
+  - if "%COMPILER%"=="mingw"  set PATH=C:\projects\deps\ninja;%PATH%
+  - if "%COMPILER%"=="mingw"  set PATH=C:\mingw-w64\x86_64-7.3.0-posix-seh-rt_v5-rev0\mingw64\bin;%PATH%
+  - if "%COMPILER%"=="mingw"  g++ --version
+  - if "%platform%"=="x86"    set GENERATOR_PLATFORM=Win32
 
 before_build:
-  - cmake . -G "%GENERATOR%" -DCMAKE_CXX_FLAGS="%CXX_FLAGS%" -DCMAKE_EXE_LINKER_FLAGS="%LINKER_FLAGS%" -DCMAKE_IGNORE_PATH="C:/Program Files/Git/usr/bin"
+  # for with_win_header build, inject the inclusion of Windows.h to the single-header library
+  - ps: if ($env:name -Eq "with_win_header") { $header_path = "single_include\nlohmann\json.hpp" }
+  - ps: if ($env:name -Eq "with_win_header") { "#include <Windows.h>`n" + (Get-Content $header_path | Out-String) | Set-Content $header_path }
+  - if "%GENERATOR%"=="Ninja" (cmake . -G "%GENERATOR%" -DCMAKE_BUILD_TYPE="%configuration%" -DCMAKE_CXX_FLAGS="%CXX_FLAGS%" -DCMAKE_EXE_LINKER_FLAGS="%LINKER_FLAGS%" -DCMAKE_IGNORE_PATH="C:/Program Files/Git/usr/bin" -DJSON_BuildTests=On) else (cmake . -G "%GENERATOR%" -A "%GENERATOR_PLATFORM%" -DCMAKE_CXX_FLAGS="%CXX_FLAGS%" -DCMAKE_EXE_LINKER_FLAGS="%LINKER_FLAGS%" -DCMAKE_IGNORE_PATH="C:/Program Files/Git/usr/bin" -DJSON_BuildTests=On)
 
 build_script:
-  - cmake --build . --config Release
+  - cmake --build . --config "%configuration%"
 
 test_script:
-  - ctest -C Release -V -j
+  - if "%configuration%"=="Release" ctest -C "%configuration%" -V -j
+  # On Debug builds, skip test-unicode_all
+  # as it is extremely slow to run and cause
+  # occasional timeouts on AppVeyor.
+  # More info: https://github.com/nlohmann/json/pull/1570
+  - if "%configuration%"=="Debug" ctest --exclude-regex "test-unicode" -C "%configuration%" -V -j

benchmarks/CMakeLists.txt

@@ -14,15 +14,12 @@ add_subdirectory(thirdparty/benchmark)
 include_directories(thirdparty)
 include_directories(${CMAKE_SOURCE_DIR}/../single_include)
 
-# copy test files to build folder
-file(COPY ${CMAKE_SOURCE_DIR}/data DESTINATION .)
-file(COPY ${CMAKE_SOURCE_DIR}/../test/data/regression/floats.json
-          ${CMAKE_SOURCE_DIR}/../test/data/regression/unsigned_ints.json
-          ${CMAKE_SOURCE_DIR}/../test/data/regression/signed_ints.json
-          ${CMAKE_SOURCE_DIR}/../test/data/regression/small_signed_ints.json
-    DESTINATION data/numbers)
+# download test data
+include(${CMAKE_SOURCE_DIR}/../cmake/download_test_data.cmake)
 
 # benchmark binary
 add_executable(json_benchmarks src/benchmarks.cpp)
 target_compile_features(json_benchmarks PRIVATE cxx_std_11)
 target_link_libraries(json_benchmarks benchmark ${CMAKE_THREAD_LIBS_INIT})
+add_dependencies(json_benchmarks download_test_data)
+target_include_directories(json_benchmarks PRIVATE ${CMAKE_BINARY_DIR}/include)

benchmarks/src/benchmarks.cpp

@@ -1,6 +1,7 @@
 #include "benchmark/benchmark.h"
 #include <nlohmann/json.hpp>
 #include <fstream>
+#include <test_data.hpp>
 
 using json = nlohmann::json;
 
@@ -28,14 +29,14 @@ static void ParseFile(benchmark::State& state, const char* filename)
     std::ifstream file(filename, std::ios::binary | std::ios::ate);
     state.SetBytesProcessed(state.iterations() * file.tellg());
 }
-BENCHMARK_CAPTURE(ParseFile, jeopardy,              "data/jeopardy/jeopardy.json");
-BENCHMARK_CAPTURE(ParseFile, canada,                "data/nativejson-benchmark/canada.json");
-BENCHMARK_CAPTURE(ParseFile, citm_catalog,          "data/nativejson-benchmark/citm_catalog.json");
-BENCHMARK_CAPTURE(ParseFile, twitter,               "data/nativejson-benchmark/twitter.json");
-BENCHMARK_CAPTURE(ParseFile, floats,                "data/numbers/floats.json");
-BENCHMARK_CAPTURE(ParseFile, signed_ints,           "data/numbers/signed_ints.json");
-BENCHMARK_CAPTURE(ParseFile, unsigned_ints,         "data/numbers/unsigned_ints.json");
-BENCHMARK_CAPTURE(ParseFile, small_signed_ints,     "data/numbers/small_signed_ints.json");
+BENCHMARK_CAPTURE(ParseFile, jeopardy,          TEST_DATA_DIRECTORY "/jeopardy/jeopardy.json");
+BENCHMARK_CAPTURE(ParseFile, canada,            TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json");
+BENCHMARK_CAPTURE(ParseFile, citm_catalog,      TEST_DATA_DIRECTORY "/nativejson-benchmark/citm_catalog.json");
+BENCHMARK_CAPTURE(ParseFile, twitter,           TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json");
+BENCHMARK_CAPTURE(ParseFile, floats,            TEST_DATA_DIRECTORY "/regression/floats.json");
+BENCHMARK_CAPTURE(ParseFile, signed_ints,       TEST_DATA_DIRECTORY "/regression/signed_ints.json");
+BENCHMARK_CAPTURE(ParseFile, unsigned_ints,     TEST_DATA_DIRECTORY "/regression/unsigned_ints.json");
+BENCHMARK_CAPTURE(ParseFile, small_signed_ints, TEST_DATA_DIRECTORY "/regression/small_signed_ints.json");
 
 //////////////////////////////////////////////////////////////////////////////
 // parse JSON from string
@@ -61,14 +62,14 @@ static void ParseString(benchmark::State& state, const char* filename)
 
     state.SetBytesProcessed(state.iterations() * str.size());
 }
-BENCHMARK_CAPTURE(ParseString, jeopardy,            "data/jeopardy/jeopardy.json");
-BENCHMARK_CAPTURE(ParseString, canada,              "data/nativejson-benchmark/canada.json");
-BENCHMARK_CAPTURE(ParseString, citm_catalog,        "data/nativejson-benchmark/citm_catalog.json");
-BENCHMARK_CAPTURE(ParseString, twitter,             "data/nativejson-benchmark/twitter.json");
-BENCHMARK_CAPTURE(ParseString, floats,              "data/numbers/floats.json");
-BENCHMARK_CAPTURE(ParseString, signed_ints,         "data/numbers/signed_ints.json");
-BENCHMARK_CAPTURE(ParseString, unsigned_ints,       "data/numbers/unsigned_ints.json");
-BENCHMARK_CAPTURE(ParseString, small_signed_ints,   "data/numbers/small_signed_ints.json");
+BENCHMARK_CAPTURE(ParseString, jeopardy,          TEST_DATA_DIRECTORY "/jeopardy/jeopardy.json");
+BENCHMARK_CAPTURE(ParseString, canada,            TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json");
+BENCHMARK_CAPTURE(ParseString, citm_catalog,      TEST_DATA_DIRECTORY "/nativejson-benchmark/citm_catalog.json");
+BENCHMARK_CAPTURE(ParseString, twitter,           TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json");
+BENCHMARK_CAPTURE(ParseString, floats,            TEST_DATA_DIRECTORY "/regression/floats.json");
+BENCHMARK_CAPTURE(ParseString, signed_ints,       TEST_DATA_DIRECTORY "/regression/signed_ints.json");
+BENCHMARK_CAPTURE(ParseString, unsigned_ints,     TEST_DATA_DIRECTORY "/regression/unsigned_ints.json");
+BENCHMARK_CAPTURE(ParseString, small_signed_ints, TEST_DATA_DIRECTORY "/regression/small_signed_ints.json");
 
 
 //////////////////////////////////////////////////////////////////////////////
@@ -88,22 +89,22 @@ static void Dump(benchmark::State& state, const char* filename, int indent)
 
     state.SetBytesProcessed(state.iterations() * j.dump(indent).size());
 }
-BENCHMARK_CAPTURE(Dump, jeopardy / -,      "data/jeopardy/jeopardy.json",                 -1);
-BENCHMARK_CAPTURE(Dump, jeopardy / 4,      "data/jeopardy/jeopardy.json",                 4);
-BENCHMARK_CAPTURE(Dump, canada / -,        "data/nativejson-benchmark/canada.json",       -1);
-BENCHMARK_CAPTURE(Dump, canada / 4,        "data/nativejson-benchmark/canada.json",       4);
-BENCHMARK_CAPTURE(Dump, citm_catalog / -,  "data/nativejson-benchmark/citm_catalog.json", -1);
-BENCHMARK_CAPTURE(Dump, citm_catalog / 4,  "data/nativejson-benchmark/citm_catalog.json", 4);
-BENCHMARK_CAPTURE(Dump, twitter / -,       "data/nativejson-benchmark/twitter.json",      -1);
-BENCHMARK_CAPTURE(Dump, twitter / 4,       "data/nativejson-benchmark/twitter.json",      4);
-BENCHMARK_CAPTURE(Dump, floats / -,        "data/numbers/floats.json",                    -1);
-BENCHMARK_CAPTURE(Dump, floats / 4,        "data/numbers/floats.json",                    4);
-BENCHMARK_CAPTURE(Dump, signed_ints / -,   "data/numbers/signed_ints.json",               -1);
-BENCHMARK_CAPTURE(Dump, signed_ints / 4,   "data/numbers/signed_ints.json",               4);
-BENCHMARK_CAPTURE(Dump, unsigned_ints / -, "data/numbers/unsigned_ints.json",             -1);
-BENCHMARK_CAPTURE(Dump, unsigned_ints / 4, "data/numbers/unsigned_ints.json",             4);
-BENCHMARK_CAPTURE(Dump, small_signed_ints / -,   "data/numbers/small_signed_ints.json",   -1);
-BENCHMARK_CAPTURE(Dump, small_signed_ints / 4,   "data/numbers/small_signed_ints.json",   4);
+BENCHMARK_CAPTURE(Dump, jeopardy / -,          TEST_DATA_DIRECTORY "/jeopardy/jeopardy.json",                 -1);
+BENCHMARK_CAPTURE(Dump, jeopardy / 4,          TEST_DATA_DIRECTORY "/jeopardy/jeopardy.json",                 4);
+BENCHMARK_CAPTURE(Dump, canada / -,            TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json",       -1);
+BENCHMARK_CAPTURE(Dump, canada / 4,            TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json",       4);
+BENCHMARK_CAPTURE(Dump, citm_catalog / -,      TEST_DATA_DIRECTORY "/nativejson-benchmark/citm_catalog.json", -1);
+BENCHMARK_CAPTURE(Dump, citm_catalog / 4,      TEST_DATA_DIRECTORY "/nativejson-benchmark/citm_catalog.json", 4);
+BENCHMARK_CAPTURE(Dump, twitter / -,           TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json",      -1);
+BENCHMARK_CAPTURE(Dump, twitter / 4,           TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json",      4);
+BENCHMARK_CAPTURE(Dump, floats / -,            TEST_DATA_DIRECTORY "/regression/floats.json",                 -1);
+BENCHMARK_CAPTURE(Dump, floats / 4,            TEST_DATA_DIRECTORY "/regression/floats.json",                 4);
+BENCHMARK_CAPTURE(Dump, signed_ints / -,       TEST_DATA_DIRECTORY "/regression/signed_ints.json",            -1);
+BENCHMARK_CAPTURE(Dump, signed_ints / 4,       TEST_DATA_DIRECTORY "/regression/signed_ints.json",            4);
+BENCHMARK_CAPTURE(Dump, unsigned_ints / -,     TEST_DATA_DIRECTORY "/regression/unsigned_ints.json",          -1);
+BENCHMARK_CAPTURE(Dump, unsigned_ints / 4,     TEST_DATA_DIRECTORY "/regression/unsigned_ints.json",          4);
+BENCHMARK_CAPTURE(Dump, small_signed_ints / -, TEST_DATA_DIRECTORY "/regression/small_signed_ints.json",      -1);
+BENCHMARK_CAPTURE(Dump, small_signed_ints / 4, TEST_DATA_DIRECTORY "/regression/small_signed_ints.json",      4);
 
 
 BENCHMARK_MAIN();

cmake/download_test_data.cmake

@@ -0,0 +1,51 @@
+find_package(Git)
+
+set(JSON_TEST_DATA_URL     https://github.com/nlohmann/json_test_data)
+set(JSON_TEST_DATA_VERSION 2.0.0)
+
+# 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}
+)
+
+# 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")
+
+# 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}")
+endif()
+if (SW_VERS_COMMAND)
+    execute_process(COMMAND ${SW_VERS_COMMAND} OUTPUT_VARIABLE SW_VERS_COMMAND_RESULT OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_QUIET)
+    string(REGEX REPLACE "[ ]*\n" "; " SW_VERS_COMMAND_RESULT "${SW_VERS_COMMAND_RESULT}")
+    set(OS_VERSION_STRINGS "${OS_VERSION_STRINGS}; ${SW_VERS_COMMAND_RESULT}")
+endif()
+if (LSB_RELEASE_COMMAND)
+    execute_process(COMMAND ${LSB_RELEASE_COMMAND} -a OUTPUT_VARIABLE LSB_RELEASE_COMMAND_RESULT OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_QUIET)
+    string(REGEX REPLACE "[ ]*\n" "; " LSB_RELEASE_COMMAND_RESULT "${LSB_RELEASE_COMMAND_RESULT}")
+    set(OS_VERSION_STRINGS "${OS_VERSION_STRINGS}; ${LSB_RELEASE_COMMAND_RESULT}")
+endif()
+if (UNAME_COMMAND)
+    execute_process(COMMAND ${UNAME_COMMAND} -a OUTPUT_VARIABLE UNAME_COMMAND_RESULT OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_QUIET)
+    set(OS_VERSION_STRINGS "${OS_VERSION_STRINGS}; ${UNAME_COMMAND_RESULT}")
+endif()
+
+message(STATUS "Operating system: ${OS_VERSION_STRINGS}")
+
+# determine the compiler (for debug and support purposes)
+if (MSVC)
+    execute_process(COMMAND ${CMAKE_CXX_COMPILER} OUTPUT_VARIABLE CXX_VERSION_RESULT OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_VARIABLE CXX_VERSION_RESULT ERROR_STRIP_TRAILING_WHITESPACE)
+    set(CMAKE_CXX_COMPILER "${CXX_VERSION_RESULT}; MSVC_VERSION=${MSVC_VERSION}; MSVC_TOOLSET_VERSION=${MSVC_TOOLSET_VERSION}")
+else()
+    execute_process(COMMAND ${CMAKE_CXX_COMPILER} --version OUTPUT_VARIABLE CXX_VERSION_RESULT OUTPUT_STRIP_TRAILING_WHITESPACE)
+endif()
+string(REGEX REPLACE "[ ]*\n" "; " CXX_VERSION_RESULT "${CXX_VERSION_RESULT}")
+message(STATUS "Compiler: ${CXX_VERSION_RESULT}")

cmake/nlohmann_jsonConfigVersion.cmake.in

@@ -0,0 +1,20 @@
+# This is essentially cmake's BasicConfigVersion-SameMajorVersion.cmake.in but
+# without the 32/64-bit check.  Since json is a header-only library, it doesn't
+# matter if it was built on a different platform than what it is used on (see
+# https://github.com/nlohmann/json/issues/1697).
+set(PACKAGE_VERSION "@PROJECT_VERSION@")
+
+if(PACKAGE_VERSION VERSION_LESS PACKAGE_FIND_VERSION)
+  set(PACKAGE_VERSION_COMPATIBLE FALSE)
+else()
+
+  if(PACKAGE_FIND_VERSION_MAJOR STREQUAL "@PROJECT_VERSION_MAJOR@")
+    set(PACKAGE_VERSION_COMPATIBLE TRUE)
+  else()
+    set(PACKAGE_VERSION_COMPATIBLE FALSE)
+  endif()
+
+  if(PACKAGE_FIND_VERSION STREQUAL PACKAGE_VERSION)
+      set(PACKAGE_VERSION_EXACT TRUE)
+  endif()
+endif()

doc/Doxyfile

@@ -1,11 +1,11 @@
-# Doxyfile 1.8.16
+# Doxyfile 1.8.19
 
 #---------------------------------------------------------------------------
 # Project related configuration options
 #---------------------------------------------------------------------------
 DOXYFILE_ENCODING      = UTF-8
 PROJECT_NAME           = "JSON for Modern C++"
-PROJECT_NUMBER         = 3.6.1
+PROJECT_NUMBER         = 3.8.0
 PROJECT_BRIEF          =
 PROJECT_LOGO           =
 OUTPUT_DIRECTORY       = .
@@ -23,6 +23,7 @@ STRIP_FROM_PATH        =
 STRIP_FROM_INC_PATH    =
 SHORT_NAMES            = NO
 JAVADOC_AUTOBRIEF      = NO
+JAVADOC_BANNER         = NO
 QT_AUTOBRIEF           = NO
 MULTILINE_CPP_IS_BRIEF = NO
 INHERIT_DOCS           = YES
@@ -33,7 +34,6 @@ ALIASES                = "complexity=@par Complexity^^" \
                          "requirement=@par Requirements^^" \
                          "exceptionsafety=@par Exception safety^^" \
                          "iterators=@par Iterator validity^^"
-TCL_SUBST              =
 OPTIMIZE_OUTPUT_FOR_C  = NO
 OPTIMIZE_OUTPUT_JAVA   = NO
 OPTIMIZE_FOR_FORTRAN   = NO
@@ -59,6 +59,7 @@ LOOKUP_CACHE_SIZE      = 0
 #---------------------------------------------------------------------------
 EXTRACT_ALL            = YES
 EXTRACT_PRIVATE        = NO
+EXTRACT_PRIV_VIRTUAL   = NO
 EXTRACT_PACKAGE        = YES
 EXTRACT_STATIC         = YES
 EXTRACT_LOCAL_CLASSES  = YES
@@ -109,9 +110,7 @@ WARN_LOGFILE           =
 # Configuration options related to the input files
 #---------------------------------------------------------------------------
 INPUT                  = ../single_include/nlohmann/json.hpp \
-                         index.md \
-                         faq.md \
-                         binary_formats.md
+                         index.md
 INPUT_ENCODING         = UTF-8
 FILE_PATTERNS          =
 RECURSIVE              = NO
@@ -140,9 +139,6 @@ REFERENCES_LINK_SOURCE = NO
 SOURCE_TOOLTIPS        = YES
 USE_HTAGS              = NO
 VERBATIM_HEADERS       = NO
-CLANG_ASSISTED_PARSING = YES
-CLANG_OPTIONS          = -std=c++11
-CLANG_DATABASE_PATH    =
 #---------------------------------------------------------------------------
 # Configuration options related to the alphabetical class index
 #---------------------------------------------------------------------------
@@ -194,8 +190,10 @@ GENERATE_TREEVIEW      = NO
 ENUM_VALUES_PER_LINE   = 4
 TREEVIEW_WIDTH         = 250
 EXT_LINKS_IN_WINDOW    = NO
+HTML_FORMULA_FORMAT    = png
 FORMULA_FONTSIZE       = 10
 FORMULA_TRANSPARENT    = YES
+FORMULA_MACROFILE      =
 USE_MATHJAX            = NO
 MATHJAX_FORMAT         = HTML-CSS
 MATHJAX_RELPATH        = http://cdn.mathjax.org/mathjax/latest
@@ -293,12 +291,10 @@ GENERATE_TAGFILE       = html/nlohmann_json.tag
 ALLEXTERNALS           = NO
 EXTERNAL_GROUPS        = YES
 EXTERNAL_PAGES         = YES
-PERL_PATH              = /usr/bin/perl
 #---------------------------------------------------------------------------
 # Configuration options related to the dot tool
 #---------------------------------------------------------------------------
 CLASS_DIAGRAMS         = NO
-MSCGEN_PATH            =
 DIA_PATH               =
 HIDE_UNDOC_RELATIONS   = YES
 HAVE_DOT               = YES

doc/Makefile

@@ -61,6 +61,8 @@ doxygen: create_output create_links
 	$(SED) -i 's@template<template< typename U, typename V, typename... Args > class ObjectType = std::map, template< typename U, typename... Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer>@@g' html/*.html
 	$(SED) -i 's@< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >@@g' html/*.html
 	$(SED) -i 's@< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >@@g' html/*.html
+	$(SED) -i 's@JSON_HEDLEY_RETURNS_NON_NULL@@g' html/*.html
+	$(SED) -i 's@JSON_HEDLEY_WARN_UNUSED_RESULT@@g' html/*.html
 
 upload: clean doxygen check_output
 	scripts/git-update-ghpages nlohmann/json html

doc/binary_formats.md

@@ -1,171 +0,0 @@
-# Binary formats
-
-![conversion between JSON and binary formats](images/binary.png)
-
-Several formats exist that encode JSON values in a binary format to reduce the size of the encoded value as well as the required effort to parse encoded value. The library implements three formats, namely
-
-- [CBOR](https://tools.ietf.org/html/rfc7049) (Concise Binary Object Representation)
-- [MessagePack](https://msgpack.org)
-- [UBJSON](http://ubjson.org) (Universal Binary JSON)
-
-## Interface
-
-### JSON to binary format
-
-For each format, the `to_*` functions (i.e., `to_cbor`, `to_msgpack`, and `to_ubjson`) convert a JSON value into the respective binary format. Taking CBOR as example, the concrete prototypes are:
-
-```cpp
-static std::vector<uint8_t> to_cbor(const basic_json& j);                    // 1
-static void to_cbor(const basic_json& j, detail::output_adapter<uint8_t> o); // 2
-static void to_cbor(const basic_json& j, detail::output_adapter<char> o);    // 3
-```
-
-The first function creates a byte vector from the given JSON value. The second and third function writes to an output adapter of `uint8_t` and `char`, respectively. Output adapters are implemented for strings, output streams, and vectors.
-
-Given a JSON value `j`, the following calls are possible:
-
-```cpp
-std::vector<uint8_t> v;
-v = json::to_cbor(j);   // 1
-
-json::to_cbor(j, v);    // 2
-
-std::string s;
-json::to_cbor(j, s);    // 3
-
-std::ostringstream oss;
-json::to_cbor(j, oss);  // 3
-```
-
-### Binary format to JSON
-
-Likewise, the `from_*` functions (i.e, `from_cbor`, `from_msgpack`, and `from_ubjson`) convert a binary encoded value into a JSON value. Taking CBOR as example, the concrete prototypes are:
-
-```cpp
-static basic_json from_cbor(detail::input_adapter i, const bool strict = true); // 1
-static basic_json from_cbor(A1 && a1, A2 && a2, const bool strict = true);      // 2
-```
-
-Both functions read from an input adapter: the first function takes it directly form argument `i`, whereas the second function creates it from the provided arguments `a1` and `a2`. If the optional parameter `strict` is true, the input must be read completely (or a parse error exception is thrown). If it is false, parsing succeeds even if the input is not completely read.
-
-Input adapters are implemented for input streams, character buffers, string literals, and iterator ranges.
-
-Given several inputs (which we assume to be filled with a CBOR value), the following calls are possible:
-
-```cpp
-std::string s;
-json j1 = json::from_cbor(s);                         // 1
-
-std::ifstream is("somefile.cbor", std::ios::binary);
-json j2 = json::from_cbor(is);                        // 1
-
-std::vector<uint8_t> v;
-json j3 = json::from_cbor(v);                         // 1
-
-const char* buff;
-std::size_t buff_size;
-json j4 = json::from_cbor(buff, buff_size);           // 2
-```
-
-## Details
-
-### CBOR
-
-The mapping from CBOR to JSON is **incomplete** in the sense that not all CBOR types can be converted to a JSON value. The following CBOR types are not supported and will yield parse errors (parse_error.112):
-
-- byte strings (0x40..0x5F)
-- date/time (0xC0..0xC1)
-- bignum (0xC2..0xC3)
-- decimal fraction (0xC4)
-- bigfloat (0xC5)
-- tagged items (0xC6..0xD4, 0xD8..0xDB)
-- expected conversions (0xD5..0xD7)
-- simple values (0xE0..0xF3, 0xF8)
-- undefined (0xF7)
-
-CBOR further allows map keys of any type, whereas JSON only allows strings as keys in object values. Therefore, CBOR maps with keys other than UTF-8 strings are rejected (parse_error.113).
-
-The mapping from JSON to CBOR is **complete** in the sense that any JSON value type can be converted to a CBOR value.
-
-If NaN or Infinity are stored inside a JSON number, they are serialized properly. This behavior differs from the dump() function which serializes NaN or Infinity to null.
-
-The following CBOR types are not used in the conversion:
-
-- byte strings (0x40..0x5F)
-- UTF-8 strings terminated by "break" (0x7F)
-- arrays terminated by "break" (0x9F)
-- maps terminated by "break" (0xBF)
-- date/time (0xC0..0xC1)
-- bignum (0xC2..0xC3)
-- decimal fraction (0xC4)
-- bigfloat (0xC5)
-- tagged items (0xC6..0xD4, 0xD8..0xDB)
-- expected conversions (0xD5..0xD7)
-- simple values (0xE0..0xF3, 0xF8)
-- undefined (0xF7)
-- half and single-precision floats (0xF9-0xFA)
-- break (0xFF)
-
-### MessagePack
-
-The mapping from MessagePack to JSON is **incomplete** in the sense that not all MessagePack types can be converted to a JSON value. The following MessagePack types are not supported and will yield parse errors:
-
-- bin 8 - bin 32 (0xC4..0xC6)
-- ext 8 - ext 32 (0xC7..0xC9)
-- fixext 1 - fixext 16 (0xD4..0xD8)
-
-The mapping from JSON to MessagePack is **complete** in the sense that any JSON value type can be converted to a MessagePack value.
-
-The following values can not be converted to a MessagePack value:
-
-- strings with more than 4294967295 bytes
-- arrays with more than 4294967295 elements
-- objects with more than 4294967295 elements
-
-The following MessagePack types are not used in the conversion:
-
-- bin 8 - bin 32 (0xC4..0xC6)
-- ext 8 - ext 32 (0xC7..0xC9)
-- float 32 (0xCA)
-- fixext 1 - fixext 16 (0xD4..0xD8)
-
-Any MessagePack output created `to_msgpack` can be successfully parsed by `from_msgpack`.
-
-If NaN or Infinity are stored inside a JSON number, they are serialized properly. This behavior differs from the `dump()` function which serializes NaN or Infinity to `null`.
-
-### UBJSON
-
-The mapping from UBJSON to JSON is **complete** in the sense that any UBJSON value can be converted to a JSON value.
-
-The mapping from JSON to UBJSON is **complete** in the sense that any JSON value type can be converted to a UBJSON value.
-
-The following values can not be converted to a UBJSON value:
-
-- strings with more than 9223372036854775807 bytes (theoretical)
-- unsigned integer numbers above 9223372036854775807
-
-The following markers are not used in the conversion:
-
-- `Z`: no-op values are not created.
-- `C`: single-byte strings are serialized with S markers.
-
-Any UBJSON output created to_ubjson can be successfully parsed by from_ubjson.
-
-If NaN or Infinity are stored inside a JSON number, they are serialized properly. This behavior differs from the `dump()` function which serializes NaN or Infinity to null.
-
-The optimized formats for containers are supported: Parameter `use_size` adds size information to the beginning of a container and removes the closing marker. Parameter `use_type` further checks whether all elements of a container have the same type and adds the type marker to the beginning of the container. The `use_type` parameter must only be used together with `use_size = true`. Note that `use_size = true` alone may result in larger representations - the benefit of this parameter is that the receiving side is immediately informed on the number of elements of the container.
-
-## Size comparison examples
-
-The following table shows the size compared to the original JSON value for different files from the repository for the different formats.
-
-| format                  | sample.json | all_unicode.json | floats.json | signed_ints.json | jeopardy.json | canada.json |
-| ----------------------- | -----------:| ----------------:| -----------:| ----------------:| -------------:| -----------:|
-| JSON                    |    100.00 % |         100.00 % |    100.00 % |         100.00 % |      100.00 % |    100.00 % |
-| CBOR                    |     87.21 % |          71.18 % |     48.20 % |          44.16 % |       87.96 % |     50.53 % |
-| MessagePack             |     87.16 % |          71.18 % |     48.20 % |          44.16 % |       87.91 % |     50.56 % |
-| UBJSON unoptimized      |     88.15 % |         100.00 % |     48.20 % |          44.16 % |       96.58 % |     53.20 % |
-| UBJSON size-optimized   |     89.26 % |         100.00 % |     48.20 % |          44.16 % |       97.40 % |     58.56 % |
-| UBJSON format-optimized |     89.45 % |         100.00 % |     42.85 % |          39.26 % |       94.96 % |     55.93 % |
-
-The results show that there does not exist a "best" encoding. Furthermore, it is not always worthwhile to use UBJSON's optimizations.

doc/examples/README.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/uAyi8CvcGwzGQ406"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/EezQxM0Nzi8tTUEe"><b>online</b></a>

doc/examples/accept__string.cpp

@@ -0,0 +1,26 @@
+#include <iostream>
+#include <iomanip>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // a valid JSON text
+    auto valid_text = R"(
+    {
+        "numbers": [1, 2, 3]
+    }
+    )";
+
+    // an invalid JSON text
+    auto invalid_text = R"(
+    {
+        "strings": ["extra", "comma", ]
+    }
+    )";
+
+    std::cout << std::boolalpha
+              << json::accept(valid_text) << ' '
+              << json::accept(invalid_text) << '\n';
+}

doc/examples/accept__string.link

@@ -0,0 +1 @@
+<a target="_blank" href="https://wandbox.org/permlink/r5Tai1spihWHTdFA"><b>online</b></a>

doc/examples/accept__string.output

@@ -0,0 +1 @@
+true false

doc/examples/array.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/piWraYhVg2CV3j2H"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/Ptk2BoNyGfrZfxRU"><b>online</b></a>

doc/examples/at__object_t_key_type.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/wtWzPSQWWiuxldVs"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/055DW3OWJPwGYr92"><b>online</b></a>

doc/examples/at__object_t_key_type_const.cpp

@@ -6,7 +6,7 @@ using json = nlohmann::json;
 int main()
 {
     // create JSON object
-    json object =
+    const json object =
     {
         {"the good", "il buono"},
         {"the bad", "il cattivo"},

doc/examples/at__object_t_key_type_const.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/Zh3iTnZNxsSgBvm3"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/gM1uqvzukokLwjMa"><b>online</b></a>

doc/examples/at__size_type.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/MfM8XIuPWMvxxdeb"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/H3tBOr4lpufGRHlF"><b>online</b></a>

doc/examples/at__size_type_const.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/eFEcnFZxfdLGSMhw"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/UtGhIQGxCYIml36F"><b>online</b></a>

doc/examples/at_json_pointer.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/ST2lraxpPLdDOUFn"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/NHe5FLR1KYaiHwBx"><b>online</b></a>

doc/examples/at_json_pointer_const.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/FkPwquIlr9pojvGf"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/lbZjdwg6yII33cV5"><b>online</b></a>

doc/examples/back.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/AxHC1Xl6KALWJ0FJ"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/swnzqmd8zj6ij1fb"><b>online</b></a>

doc/examples/basic_json__CompatibleType.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/pylFciQUhOx6zXW8"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/RodBcX8vpcP5dQ40"><b>online</b></a>

doc/examples/basic_json__InputIt_InputIt.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/KCfRvbW3QTvghlFb"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/oWFo4AhVlMBjNv8E"><b>online</b></a>

doc/examples/basic_json__basic_json.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/TM0OkdSgEIGBDbrv"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/oRn0YsYyurs0Zi5T"><b>online</b></a>

doc/examples/basic_json__copyassignment.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/jWDJPXw490IFoVL1"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/kVknQzPMpqjywTpG"><b>online</b></a>

doc/examples/basic_json__list_init_t.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/FR2ImEj05R1bqqZ2"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/yzkjGGzMOESBkCdH"><b>online</b></a>

doc/examples/basic_json__moveconstructor.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/XTHN0lMT9QsmBcBy"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/eIOvQiuID2qgxp5u"><b>online</b></a>

doc/examples/basic_json__nullptr_t.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/iCwvXJinCVY7q1vi"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/Vm0nR32x6co8rq40"><b>online</b></a>

doc/examples/basic_json__size_type_basic_json.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/BzyeWqt4uTQ2nbfx"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/w4TtEQzlVyokIrtp"><b>online</b></a>

doc/examples/basic_json__value.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/zFWa3Zyot2oM3Z8O"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/mNy1nyabOkeHfHGf"><b>online</b></a>

doc/examples/basic_json__value_ptr.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/ECfvMr4m68Mfr192"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/a3H6kpORXgbVXylv"><b>online</b></a>

doc/examples/basic_json__value_t.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/LNck7Gktm14bmPy0"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/yXZGDwDHH3LOuFIr"><b>online</b></a>

doc/examples/begin.cpp

@@ -8,7 +8,7 @@ int main()
     // create an array value
     json array = {1, 2, 3, 4, 5};
 
-    // get am iterator to the first element
+    // get an iterator to the first element
     json::iterator it = array.begin();
 
     // serialize the element that the iterator points to

doc/examples/begin.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/xKAi3HGAdCU5y2dS"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/fS4kfQG1hmhjMScn"><b>online</b></a>

doc/examples/cbegin.cpp

@@ -8,7 +8,7 @@ int main()
     // create an array value
     const json array = {1, 2, 3, 4, 5};
 
-    // get am iterator to the first element
+    // get an iterator to the first element
     json::const_iterator it = array.cbegin();
 
     // serialize the element that the iterator points to

doc/examples/cbegin.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/oKNo3GDUa9cxjgVB"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/hxcSxCPPLHpZMxjS"><b>online</b></a>

doc/examples/cend.cpp

@@ -8,7 +8,7 @@ int main()
     // create an array value
     json array = {1, 2, 3, 4, 5};
 
-    // get am iterator to one past the last element
+    // get an iterator to one past the last element
     json::const_iterator it = array.cend();
 
     // decrement the iterator to point to the last element

doc/examples/cend.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/mP4cOSG4MtXmXlFw"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/xbnldrrN05tKIOEv"><b>online</b></a>

doc/examples/clear.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/0W6xYpQWS5Kd64CF"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/gDQPYFxMrvD7RK4z"><b>online</b></a>

doc/examples/contains.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/iHSlXjtjhgO9Q1Tw"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/vVY4F4xKC3v6pG6F"><b>online</b></a>

doc/examples/contains_json_pointer.cpp

@@ -0,0 +1,42 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // create a JSON value
+    json j =
+    {
+        {"number", 1}, {"string", "foo"}, {"array", {1, 2}}
+    };
+
+    std::cout << std::boolalpha
+              << j.contains("/number"_json_pointer) << '\n'
+              << j.contains("/string"_json_pointer) << '\n'
+              << j.contains("/array"_json_pointer) << '\n'
+              << j.contains("/array/1"_json_pointer) << '\n'
+              << j.contains("/array/-"_json_pointer) << '\n'
+              << j.contains("/array/4"_json_pointer) << '\n'
+              << j.contains("/baz"_json_pointer) << std::endl;
+
+    try
+    {
+        // try to use an array index with leading '0'
+        j.contains("/array/01"_json_pointer);
+    }
+    catch (json::parse_error& e)
+    {
+        std::cout << e.what() << '\n';
+    }
+
+    try
+    {
+        // try to use an array index that is not a number
+        j.contains("/array/one"_json_pointer);
+    }
+    catch (json::parse_error& e)
+    {
+        std::cout << e.what() << '\n';
+    }
+}

doc/examples/contains_json_pointer.link

@@ -0,0 +1 @@
+<a target="_blank" href="https://wandbox.org/permlink/Q2GTzxF8NA10kVvD"><b>online</b></a>

doc/examples/contains_json_pointer.output

@@ -0,0 +1,7 @@
+true
+true
+true
+true
+false
+false
+false

doc/examples/count.cpp

@@ -8,7 +8,7 @@ int main()
     // create a JSON object
     json j_object = {{"one", 1}, {"two", 2}};
 
-    // call find
+    // call count()
     auto count_two = j_object.count("two");
     auto count_three = j_object.count("three");
 

doc/examples/count.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/4qmbLSA75stzPgtZ"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/6LRjg1bqwchPUoDx"><b>online</b></a>

doc/examples/crbegin.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/mcjh1kDXXkzq7TxM"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/JMDd9jiP0flRKJ6C"><b>online</b></a>

doc/examples/crend.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/6tH3hnp53iVzAQZQ"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/HdlqwPk8bDfrZ4AE"><b>online</b></a>

doc/examples/diff.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/3OPLSVPyweUyEHaX"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/GHVHgDpT5vx0KMPD"><b>online</b></a>

doc/examples/dump.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/KtH6hJIe10abhHMi"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/DyMiKrkKMwd3R7OU"><b>online</b></a>

doc/examples/emplace.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/zIQBGY6fKqiMmbvb"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/p9P3Ph8mdxMON6SY"><b>online</b></a>

doc/examples/emplace_back.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/QEbpCnjGIpFWmYbE"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/yMxKrJfRedlFygJD"><b>online</b></a>

doc/examples/empty.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/AcEmkGmmmz0dPdHW"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/zaexgkNdH3HYJm8D"><b>online</b></a>

doc/examples/end.cpp

@@ -8,7 +8,7 @@ int main()
     // create an array value
     json array = {1, 2, 3, 4, 5};
 
-    // get am iterator to one past the last element
+    // get an iterator to one past the last element
     json::iterator it = array.end();
 
     // decrement the iterator to point to the last element

doc/examples/end.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/rSTMI3VXUFtNCWNc"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/eQ0YI8wWcMIHtBCS"><b>online</b></a>

doc/examples/erase__IteratorType.cpp

@@ -13,7 +13,7 @@ int main()
     json j_array = {1, 2, 4, 8, 16};
     json j_string = "Hello, world";
 
-    // call erase
+    // call erase()
     j_boolean.erase(j_boolean.begin());
     j_number_integer.erase(j_number_integer.begin());
     j_number_float.erase(j_number_float.begin());

doc/examples/erase__IteratorType.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/nh51Nho7iuAAAPyk"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/SD62jUgeIuudweZu"><b>online</b></a>

doc/examples/erase__IteratorType_IteratorType.cpp

@@ -13,7 +13,7 @@ int main()
     json j_array = {1, 2, 4, 8, 16};
     json j_string = "Hello, world";
 
-    // call erase
+    // call erase()
     j_boolean.erase(j_boolean.begin(), j_boolean.end());
     j_number_integer.erase(j_number_integer.begin(), j_number_integer.end());
     j_number_float.erase(j_number_float.begin(), j_number_float.end());

doc/examples/erase__IteratorType_IteratorType.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/xqf45a27zQqgthtB"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/gG3bN97HOF04Xw6S"><b>online</b></a>

doc/examples/erase__key_type.cpp

@@ -8,7 +8,7 @@ int main()
     // create a JSON object
     json j_object = {{"one", 1}, {"two", 2}};
 
-    // call erase
+    // call erase()
     auto count_one = j_object.erase("one");
     auto count_three = j_object.erase("three");
 

doc/examples/erase__key_type.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/lMcaGzTQuWn44ly1"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/WSnobkZJZHUPUIRF"><b>online</b></a>

doc/examples/erase__size_type.cpp

@@ -8,7 +8,7 @@ int main()
     // create a JSON array
     json j_array = {0, 1, 2, 3, 4, 5};
 
-    // call erase
+    // call erase()
     j_array.erase(2);
 
     // print values

doc/examples/erase__size_type.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/7fA2QoclBNAGZprY"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/GGoqGtqEzxAsAKnI"><b>online</b></a>

doc/examples/exception.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/9ESgIBWRarZRJvCw"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/vky6QCTCqtUnNVlD"><b>online</b></a>

doc/examples/find__key_type.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/AQubfCmv848Q66Zi"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/aQjZSjuuDUxXQCjJ"><b>online</b></a>

doc/examples/flatten.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/4bn447WQbTERfBaL"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/moO4IdryeGS8QmKo"><b>online</b></a>

doc/examples/from_bson.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/qtfoxfHO7u4eKMcO"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/Q7O1liz5QrgQynqQ"><b>online</b></a>

doc/examples/from_cbor.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/AHKW5EMQN4YQ68TY"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/AjdbchxfTsN9PHCL"><b>online</b></a>

doc/examples/from_msgpack.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/J0KoQF8sOpdMg4kN"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/TdJfkKx0RAH5NB62"><b>online</b></a>

doc/examples/from_ubjson.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/uuQK0DAjhbSd96K6"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/GG9VzOZh1MDeTSsK"><b>online</b></a>

doc/examples/front.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/5NtCbAfPzCmmPd5S"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/LtqaiI6oRplSg0KI"><b>online</b></a>

doc/examples/get__PointerType.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/frQdC0nigwUVSZ21"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/ddVSXnbULrNrCbRs"><b>online</b></a>

doc/examples/get__ValueType_const.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/M4EHlf0MaujBQlub"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/QjVgxx0bwbKuE9HI"><b>online</b></a>

doc/examples/get_ptr.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/G1pg9ZBD5n15TZli"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/eA1KrytMlQl1SURe"><b>online</b></a>

doc/examples/get_ref.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/eKlCbdm2UdqXs3hS"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/jVaWWe3kAjKKn99V"><b>online</b></a>

doc/examples/get_to.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/QxtxaO6JZAMJPutC"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/UvdMlXdPnXFUq1lJ"><b>online</b></a>