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Author SHA1 Message Date
Niels Lohmann 29a647a08b Correct documentation errors found while hunting for bugs
- patch/patch_inplace: list the JSON pointer errors parse_error.106-109
  and out_of_range.402/404, and quote the actual parse_error.105 message.
- unflatten: list parse_error.106/107/108 and out_of_range.404.
- to_bson: list out_of_range.415 (binary subtype above 255) and note
  that 412 and 415 are new in 3.13.0.
- to_string: state that string_t must be convertible to std::string, also
  in the StringType requirements table.
- JSON Lines: a `while (input >> j)` loop also throws after the last value
  for concatenated JSON values; show a loop that works for both.
- BON8: a string gets 0xFF only if nothing follows it in the message; a
  string at the end of an array or object is ended by 0xFE.
- custom_string_type.hpp: add operator+=(char), which the "Always
  required" list asks for (json_pointer::to_string, flatten, unflatten,
  and diff did not compile), and an ADL int_to_string for diff and items.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-29 19:50:03 +02:00
Niels Lohmann 8ee8bff661 Say the library is available as a single header and mention json_fwd.hpp
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-29 18:28:16 +02:00
Niels Lohmann 8ead67cc30 Correct the duplicate-key recipe's claim about SAX positions
The SAX interface's key() receives no position either; only parse_error()
does. Also note that the recipe does not report the path to the repeated
key (see discussion #5085).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-29 18:18:03 +02:00
Niels Lohmann aea2132069 Keep the customer links that could not be fixed
A dead link on the customers page is still the evidence of where the
use of the library was documented. Keep the original URLs of the entries
without a working replacement (Marne, Cisco Webex Desk Camera, Philips
Hue, CyberArk) and exclude exactly these URLs from the link check.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-29 17:37:30 +02:00
Niels Lohmann 526b6d3fd6 Review and extend the documentation, and check it in CI
A review of all documentation pages found factual errors, dead links,
missing cross-references, and gaps in examples. This fixes them and adds
checks so the same problems are caught automatically.

Fixes:
- wrong signatures and version histories (operator!= C++20 member,
  binary() subtype type, get<PointerType>(), JSON_NO_THREAD_LOCAL, ...)
- stale descriptions (number parsing since #5283, UBJSON table, SAX
  example that no longer compiled, tsl::ordered_map advice)
- dead internal and external links; repology.org badges (the domain is
  suspended) replaced by badges that query the registries directly
- deprecation notes link the migration guide; the guide itself fixed

Additions:
- "See also" sections, cross-references, 25 runnable examples, 12
  Mermaid diagrams, new API pages for json_pointer::operator<=> and
  byte_container_with_subtype::operator==/!=
- landing page, guides for untrusted input and performance
- "unreleased" badge after versions newer than the latest release

Checks:
- strict documentation build (broken links/anchors fail it); CI and
  the publish workflow fetch the full history the build needs
- weekly external link check, Mermaid syntax check in CI
- check_structure.py: example titles, heading levels, alt texts,
  header links, docset index coverage; its unused-example check works
  again
- all examples produce the same output on every platform

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-29 17:05:35 +02:00
275 changed files with 5320 additions and 622 deletions
+10
View File
@@ -142,6 +142,16 @@ The documentation will then be available at <http://127.0.0.1:8000/>. See the do
[mkdocs](https://www.mkdocs.org) and [Material for MkDocs](https://squidfunk.github.io/mkdocs-material/) for more
information.
Before opening a pull request, check the documentation like the CI does:
```shell
make build -C docs/mkdocs # strict build: fails on broken links, anchors, and structure problems
make check_mermaid -C docs/mkdocs # checks the Mermaid diagrams (requires Node.js)
```
A new API page also needs an entry in [`docs/docset/docSet.sql`](https://github.com/nlohmann/json/blob/develop/docs/docset/docSet.sql),
the search index of the docset; `make build` reports missing entries.
### Amalgamate the source code
The single-header files
+11
View File
@@ -18,6 +18,17 @@ updates:
cooldown:
default-days: 7
- package-ecosystem: npm
directory: /docs/mkdocs/scripts/mermaid
schedule:
interval: daily
cooldown:
default-days: 7
ignore:
# Material for MkDocs loads mermaid@11; keep the checker on the same major version
- dependency-name: mermaid
update-types: ["version-update:semver-major"]
- package-ecosystem: pip
directory: /tools/astyle
schedule:
+46
View File
@@ -0,0 +1,46 @@
name: Check documentation links
# check the links of the documentation weekly; external links break without any change in this repository
on:
schedule:
- cron: '17 4 * * 1'
workflow_dispatch:
permissions:
contents: read
concurrency:
group: ${{ github.workflow }}
cancel-in-progress: true
jobs:
check_docs_links:
if: github.repository == 'nlohmann/json'
runs-on: ubuntu-latest
timeout-minutes: 30
steps:
- name: Harden Runner
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Install virtual environment
run: make install_venv -C docs/mkdocs
- name: Check links
shell: bash # adds -o pipefail, so tee does not hide the exit code
run: make link_check -C docs/mkdocs 2>&1 | tee link_check.log
- name: Summarize broken links
if: failure()
run: |
{
echo '### Broken documentation links'
echo '```'
grep 'invalid url' link_check.log || true
echo '```'
} >> "$GITHUB_STEP_SUMMARY"
@@ -31,6 +31,10 @@ jobs:
egress-policy: audit
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
# the git-revision-date-localized plugin needs the history for correct "last update" dates and so the
# strict build does not fail on a shallow clone
fetch-depth: 0
- name: Install virtual environment
run: make install_venv -C docs/mkdocs
+7 -1
View File
@@ -389,7 +389,7 @@ jobs:
runs-on: ubuntu-latest
strategy:
matrix:
target: [ci_test_examples, ci_test_build_documentation]
target: [ci_test_examples, ci_test_build_documentation, ci_test_documentation_mermaid]
steps:
- name: Harden Runner
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
@@ -399,6 +399,12 @@ jobs:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
# the git-revision-date-localized plugin needs the history; a shallow clone makes the strict build fail
fetch-depth: ${{ matrix.target == 'ci_test_build_documentation' && '0' || '1' }}
- uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
if: matrix.target == 'ci_test_documentation_mermaid'
with:
node-version: 24
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
+2
View File
@@ -28,6 +28,8 @@
/docs/docset/docSet.dsidx
/docs/mkdocs/.cache/
/docs/mkdocs/docs/__pycache__/
/docs/mkdocs/hooks/__pycache__/
/docs/mkdocs/scripts/mermaid/node_modules/
/docs/mkdocs/site/
/docs/mkdocs/venv/
-1
View File
@@ -13,7 +13,6 @@
[![Documentation](https://img.shields.io/badge/docs-mkdocs-blue.svg)](https://json.nlohmann.me)
[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/develop/LICENSE.MIT)
[![GitHub Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
[![Packaging status](https://repology.org/badge/tiny-repos/nlohmann-json.svg)](https://repology.org/project/nlohmann-json/versions)
[![GitHub Downloads](https://img.shields.io/github/downloads/nlohmann/json/total)](https://github.com/nlohmann/json/releases)
[![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")
+6
View File
@@ -849,6 +849,12 @@ add_custom_target(ci_test_build_documentation
COMMENT "Build the documentation"
)
add_custom_target(ci_test_documentation_mermaid
COMMAND make check_mermaid
WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/docs/mkdocs
COMMENT "Check the Mermaid diagrams of the documentation"
)
###############################################################################
# Clean up all generated files.
###############################################################################
+3 -2
View File
@@ -35,9 +35,10 @@ create_output: $(EXAMPLES:.cpp=.output)
# check output of all stand-alone example files
check_output: $(EXAMPLES:.cpp=.test)
# check output of all stand-alone example files (exclude files with platform-dependent output.)
# check output of all stand-alone example files (exclude files whose output depends on the platform by nature:
# library and compiler information, container size limits, and hash values)
# This target is used in the CI (ci_test_documentation).
check_output_portable: $(filter-out mkdocs/docs/examples/meta.test mkdocs/docs/examples/max_size.test mkdocs/docs/examples/std_hash.test mkdocs/docs/examples/basic_json__CompatibleType.test,$(EXAMPLES:.cpp=.test))
check_output_portable: $(filter-out mkdocs/docs/examples/meta.test mkdocs/docs/examples/max_size.test mkdocs/docs/examples/std_hash.test,$(EXAMPLES:.cpp=.test))
clean:
rm -fr $(EXAMPLES:.cpp=)
+35
View File
@@ -10,9 +10,12 @@ INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype',
INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::byte_container_with_subtype', 'Constructor', 'api/byte_container_with_subtype/byte_container_with_subtype/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::clear_subtype', 'Method', 'api/byte_container_with_subtype/clear_subtype/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::has_subtype', 'Method', 'api/byte_container_with_subtype/has_subtype/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::operator!=', 'Operator', 'api/byte_container_with_subtype/operator_ne/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::operator==', 'Operator', 'api/byte_container_with_subtype/operator_eq/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::set_subtype', 'Method', 'api/byte_container_with_subtype/set_subtype/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::subtype', 'Method', 'api/byte_container_with_subtype/subtype/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json', 'Class', 'api/basic_json/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('format_as', 'Function', 'api/basic_json/format_as/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::accept', 'Function', 'api/basic_json/accept/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::array', 'Function', 'api/basic_json/array/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::array_t', 'Type', 'api/basic_json/array_t/index.html');
@@ -132,15 +135,19 @@ INSERT INTO searchIndex(name, type, path) VALUES ('json', 'Class', 'api/json/ind
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer', 'Class', 'api/json_pointer/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::back', 'Method', 'api/json_pointer/back/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::empty', 'Method', 'api/json_pointer/empty/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::front', 'Method', 'api/json_pointer/front/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::json_pointer', 'Constructor', 'api/json_pointer/json_pointer/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::operator==', 'Operator', 'api/json_pointer/operator_eq/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::operator!=', 'Operator', 'api/json_pointer/operator_ne/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::operator/', 'Operator', 'api/json_pointer/operator_slash/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::operator/=', 'Operator', 'api/json_pointer/operator_slasheq/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::operator string_t', 'Operator', 'api/json_pointer/operator_string_t/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::operator<=>', 'Operator', 'api/json_pointer/operator_spaceship/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::parent_pointer', 'Method', 'api/json_pointer/parent_pointer/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::pop_back', 'Method', 'api/json_pointer/pop_back/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::pop_front', 'Method', 'api/json_pointer/pop_front/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::push_back', 'Method', 'api/json_pointer/push_back/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::push_front', 'Method', 'api/json_pointer/push_front/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::string_t', 'Type', 'api/json_pointer/string_t/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::to_string', 'Method', 'api/json_pointer/to_string/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_sax', 'Class', 'api/json_sax/index.html');
@@ -163,6 +170,7 @@ INSERT INTO searchIndex(name, type, path) VALUES ('operator<<', 'Operator', 'api
INSERT INTO searchIndex(name, type, path) VALUES ('operator>>', 'Operator', 'api/operator_gtgt/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json', 'Class', 'api/ordered_json/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map', 'Class', 'api/ordered_map/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('std::formatter<basic_json>', 'Class', 'api/basic_json/std_formatter/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('std::hash<basic_json>', 'Class', 'api/basic_json/std_hash/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('std::swap<basic_json>', 'Function', 'api/basic_json/std_swap/index.html');
@@ -195,17 +203,20 @@ INSERT INTO searchIndex(name, type, path) VALUES ('nlohmann Namespace', 'Guide',
INSERT INTO searchIndex(name, type, path) VALUES ('Types', 'Guide', 'features/types/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Types: Number Handling', 'Guide', 'features/types/number_handling/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Object Order', 'Guide', 'features/object_order/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Performance', 'Guide', 'features/performance/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Parsing', 'Guide', 'features/parsing/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Parsing: JSON Lines', 'Guide', 'features/parsing/json_lines/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Parsing: Parser Callbacks', 'Guide', 'features/parsing/parser_callbacks/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Parsing: Parsing and Exceptions', 'Guide', 'features/parsing/parse_exceptions/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Parsing: SAX Interface', 'Guide', 'features/parsing/sax_interface/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Parsing: Untrusted Input', 'Guide', 'features/parsing/untrusted_input/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Runtime Assertions', 'Guide', 'features/assertions/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Specializing enum conversion', 'Guide', 'features/enum_conversion/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Supported Macros', 'Guide', 'features/macros/index.html');
-- Macros
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_ASSERT', 'Macro', 'api/macros/json_assert/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_BRACE_INIT_COPY_SEMANTICS', 'Macro', 'api/macros/json_brace_init_copy_semantics/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_CATCH_USER', 'Macro', 'api/macros/json_throw_user/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_DIAGNOSTICS', 'Macro', 'api/macros/json_diagnostics/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_DIAGNOSTIC_POSITIONS', 'Macro', 'api/macros/json_diagnostic_positions/index.html');
@@ -214,34 +225,58 @@ INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_CPP_11', 'Macro', 'a
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_CPP_14', 'Macro', 'api/macros/json_has_cpp_11/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_CPP_17', 'Macro', 'api/macros/json_has_cpp_11/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_CPP_20', 'Macro', 'api/macros/json_has_cpp_11/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_CPP_23', 'Macro', 'api/macros/json_has_cpp_11/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_CPP_26', 'Macro', 'api/macros/json_has_cpp_11/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_EXPERIMENTAL_FILESYSTEM', 'Macro', 'api/macros/json_has_filesystem/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_FILESYSTEM', 'Macro', 'api/macros/json_has_filesystem/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_RANGES', 'Macro', 'api/macros/json_has_ranges/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_STATIC_RTTI', 'Macro', 'api/macros/json_has_static_rtti/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_STD_FORMAT', 'Macro', 'api/macros/json_has_std_format/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_THREE_WAY_COMPARISON', 'Macro', 'api/macros/json_has_three_way_comparison/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_NOEXCEPTION', 'Macro', 'api/macros/json_noexception/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_NO_IO', 'Macro', 'api/macros/json_no_io/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_NO_THREAD_LOCAL', 'Macro', 'api/macros/json_no_thread_local/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_PRECISE_STREAM_POSITION', 'Macro', 'api/macros/json_precise_stream_position/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_SKIP_LIBRARY_VERSION_CHECK', 'Macro', 'api/macros/json_skip_library_version_check/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_SKIP_UNSUPPORTED_COMPILER_CHECK', 'Macro', 'api/macros/json_skip_unsupported_compiler_check/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_STRICT_NUL_HANDLING', 'Macro', 'api/macros/json_strict_nul_handling/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_THROW_USER', 'Macro', 'api/macros/json_throw_user/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_TRY_USER', 'Macro', 'api/macros/json_throw_user/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_USE_GLOBAL_UDLS', 'Macro', 'api/macros/json_use_global_udls/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_USE_IMPLICIT_CONVERSIONS', 'Macro', 'api/macros/json_use_implicit_conversions/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON', 'Macro', 'api/macros/json_use_legacy_discarded_value_comparison/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON_USE_SIMDUTF', 'Macro', 'api/macros/json_use_simdutf/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Macros', 'Macro', 'api/macros/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE', 'Macro', 'api/macros/nlohmann_define_derived_type/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE', 'Macro', 'api/macros/nlohmann_define_derived_type/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES', 'Macro', 'api/macros/nlohmann_define_type_with_names/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT', 'Macro', 'api/macros/nlohmann_define_derived_type/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES', 'Macro', 'api/macros/nlohmann_define_type_with_names/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_NAMES', 'Macro', 'api/macros/nlohmann_define_type_with_names/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE', 'Macro', 'api/macros/nlohmann_define_derived_type/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE', 'Macro', 'api/macros/nlohmann_define_derived_type/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES', 'Macro', 'api/macros/nlohmann_define_type_with_names/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT', 'Macro', 'api/macros/nlohmann_define_derived_type/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES', 'Macro', 'api/macros/nlohmann_define_type_with_names/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_NAMES', 'Macro', 'api/macros/nlohmann_define_type_with_names/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_TYPE_INTRUSIVE', 'Macro', 'api/macros/nlohmann_define_type_intrusive/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE', 'Macro', 'api/macros/nlohmann_define_type_intrusive/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES', 'Macro', 'api/macros/nlohmann_define_type_with_names/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT', 'Macro', 'api/macros/nlohmann_define_type_intrusive/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES', 'Macro', 'api/macros/nlohmann_define_type_with_names/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_NAMES', 'Macro', 'api/macros/nlohmann_define_type_with_names/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE', 'Macro', 'api/macros/nlohmann_define_type_non_intrusive/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE', 'Macro', 'api/macros/nlohmann_define_type_non_intrusive/index.html');
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+12 -1
View File
@@ -1,3 +1,8 @@
# The MkDocs 2.0 banners of Material for MkDocs and ProperDocs (via mkdocs-redirects) are printed to stderr, not
# logged, so they do not affect --strict; silence them anyway.
export NO_MKDOCS_2_WARNING := true
export DISABLE_MKDOCS_2_WARNING := true
# serve the site locally
serve: style_check
venv/bin/mkdocs serve
@@ -8,11 +13,17 @@ serve_dirty: style_check
# This target is used in the CI (ci_test_build_documentation).
# This target is used by the docset Makefile.
build: style_check
venv/bin/mkdocs build
venv/bin/mkdocs build --strict
style_check:
@cd docs ; ../venv/bin/python3 ../scripts/check_structure.py
# check that all Mermaid diagrams parse (needs Node.js)
# This target is used in the CI (ci_test_documentation_mermaid).
check_mermaid:
npm ci --prefix scripts/mermaid --ignore-scripts --no-audit --no-fund
node scripts/mermaid/check_mermaid.mjs docs
# check the links in the documentation files in docs/mkdocs
link_check:
ENABLED_HTMLPROOFER=true venv/bin/mkdocs build
+18 -1
View File
@@ -96,7 +96,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
## Examples
??? example
??? example "Example: (1) reading from a string"
The example below demonstrates the `accept()` function reading from a string.
@@ -110,6 +110,21 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/accept__string.output"
```
??? example "Example: (2) reading from an iterator pair"
The example below demonstrates the `accept()` function reading from an iterator pair. Only the first call covers
exactly the JSON text; the second one also covers the trailing bytes and is therefore rejected.
```cpp
--8<-- "examples/accept__iterator_pair.cpp"
```
Output:
```json
--8<-- "examples/accept__iterator_pair.output"
```
## See also
- [parse](parse.md) - deserialize from a compatible input
@@ -137,3 +152,5 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#parsing) for how to update existing code.
+10 -3
View File
@@ -25,7 +25,7 @@ To store objects in C++, a type is defined by the template parameters explained
## Notes
#### Default type
### Default type
With the default values for `ArrayType` (`std::vector`) and `AllocatorType` (`std::allocator`), the default value for
`array_t` is:
@@ -37,7 +37,7 @@ std::vector<
>
```
#### Limits
### Limits
[RFC 8259](https://tools.ietf.org/html/rfc8259) specifies:
> An implementation may set limits on the maximum depth of nesting.
@@ -46,7 +46,7 @@ In this class, the array's limit of nesting is not explicitly constrained. Howev
introduced by the compiler or runtime environment. A theoretical limit can be queried by calling the
[`max_size`](max_size.md) function of a JSON array.
#### Storage
### Storage
Arrays are stored as pointers in a `basic_json` type. That is, for any access to array values, a pointer of type
`#!cpp array_t*` must be dereferenced.
@@ -67,6 +67,13 @@ Arrays are stored as pointers in a `basic_json` type. That is, for any access to
--8<-- "examples/array_t.output"
```
## See also
- [object_t](object_t.md) the type used to store JSON objects
- [binary_t](binary_t.md) the type used to store binary values
- [is_array](is_array.md) checks whether the JSON value is an array
- [max_size](max_size.md) returns the maximum possible number of elements
## Version history
- Added in version 1.0.0.
+14
View File
@@ -92,6 +92,20 @@ Strong exception safety: if an exception occurs, the original value stays intact
3. Logarithmic in the size of the container.
4. Logarithmic in the size of the container.
## Notes
!!! warning "Deprecation"
Overload (4) also accepts a [`json_pointer`](../json_pointer/index.md) whose template argument is a `basic_json`
specialization (e.g., `nlohmann::json_pointer<nlohmann::json>`) instead of a string type. This is deprecated since
version 3.11.0 and will be removed in a future major version; use `basic_json::json_pointer` (for `json`,
`nlohmann::json_pointer<std::string>`) instead.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#json-pointers) for how to update existing code.
## Examples
??? example "Example: (1) access specified array element with bounds checking"
+46 -2
View File
@@ -99,6 +99,25 @@ basic_json(basic_json&& other) noexcept;
elements of the pairs are treated as keys and the second elements are as values.
3. In all other cases, an array is created.
The following flowchart also takes into account what happens when `type_deduction` is `#!cpp false`, in which case
`manual_type` decides between object and array, and an object can only be forced if `init` actually matches rule 2
(or is empty):
```mermaid
flowchart TD
A(["initializer_list init"]) --> B{"empty, or every element is a 2-element<br/>array whose first element is a string?"}
B -->|"yes"| C{"type_deduction"}
B -->|"no"| D{"type_deduction"}
C -->|"true"| OBJ["create object"]
C -->|"false"| E{"manual_type"}
E -->|"object"| OBJ
E -->|"array"| ARR["create array"]
D -->|"true"| ARR
D -->|"false"| F{"manual_type"}
F -->|"array"| ARR
F -->|"object"| ERR["throw type_error.301"]
```
The rules aim to create the best fit between a C++ initializer list and JSON values. The rationale is as follows:
1. The empty initializer list is written as `#!cpp {}` which is exactly an empty JSON object.
@@ -169,8 +188,8 @@ basic_json(basic_json&& other) noexcept;
- `BasicJsonType` has different template arguments than `basic_json_t`.
**Note:** For cross-`basic_json` conversions to produce correct results, the target `basic_json`'s
`object_t::key_type` and `string_t` must be directly constructible from the source `basic_json`'s
corresponding types. See the description of overload (4) above for details on what happens when
[`object_t`](object_t.md)`::key_type` and [`string_t`](string_t.md) must be directly constructible from the source
`basic_json`'s corresponding types. See the description of overload (4) above for details on what happens when
this requirement is not met.
`U`:
@@ -345,6 +364,22 @@ basic_json(basic_json&& other) noexcept;
Note the output is platform-dependent.
??? example "Example: (4) create a JSON value from another `basic_json` specialization"
The example below shows how a `json` value is converted to an `ordered_json` value and back using the converting
constructor. Note how the original insertion order of `oj` is not restored, because it was already given up when
converting to `json`, whose `object_t` sorts by key.
```cpp
--8<-- "examples/basic_json__BasicJsonType.cpp"
```
Output:
```json
--8<-- "examples/basic_json__BasicJsonType.output"
```
??? example "Example: (5) create a container (array or object) from an initializer list"
The example below shows how JSON values are created from initializer lists.
@@ -415,6 +450,15 @@ basic_json(basic_json&& other) noexcept;
--8<-- "examples/basic_json__moveconstructor.output"
```
## See also
- [array](array.md) create a JSON array value, forcing array creation from an initializer list even when it looks like
an object
- [object](object.md) create a JSON object value, forcing object creation from an initializer list
- [binary](binary.md) create a JSON binary array value
- [operator=](operator=.md) copy assignment operator
- [Creating JSON values](../../features/creating_values.md) - the article on creating JSON values
## Version history
1. Since version 1.0.0.
+8
View File
@@ -37,6 +37,14 @@ Constant.
--8<-- "examples/begin.output"
```
## See also
- [end](end.md) returns an iterator to one past the last element
- [cbegin](cbegin.md) returns a const iterator to the first element
- [rbegin](rbegin.md) returns a reverse iterator to the last element
- [items](items.md) returns an iteration proxy to access keys and values during range-based for loops
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
- Added in version 1.0.0.
+11 -2
View File
@@ -7,9 +7,9 @@ static basic_json binary(typename binary_t::container_type&& init);
// (2)
static basic_json binary(const typename binary_t::container_type& init,
std::uint8_t subtype);
typename binary_t::subtype_type subtype);
static basic_json binary(typename binary_t::container_type&& init,
std::uint8_t subtype);
typename binary_t::subtype_type subtype);
```
1. Creates a JSON binary array value from a given binary container.
@@ -61,6 +61,15 @@ initialization of a binary array type, for backwards compatibility and so it doe
--8<-- "examples/binary.output"
```
## See also
- [binary_t](binary_t.md) type for binary values
- [get_binary](get_binary.md) get a reference to the stored binary value
- [is_binary](is_binary.md) return whether the value is binary
- [byte_container_with_subtype](../byte_container_with_subtype/index.md) container for binary values with subtype
- [Binary Values](../../features/binary_values.md) - the article on binary values
## Version history
- Added in version 3.8.0.
- Changed the type of `subtype` from `std::uint8_t` to `binary_t::subtype_type` (`std::uint64_t`) in version 3.10.0.
+5 -5
View File
@@ -48,16 +48,16 @@ represent a byte array in modern C++.
## Notes
#### Default type
### Default type
The default values for `BinaryType` is `#!cpp std::vector<std::uint8_t>`.
#### Supported byte types
### Supported byte types
`#!cpp std::vector<std::uint8_t>`, `#!cpp std::vector<char>`, and `#!cpp std::vector<std::byte>` are supported.
Regardless of which of them is configured, [`dump`](dump.md) writes the bytes as the numbers 0..255.
#### Custom BinaryType behavior
### Custom BinaryType behavior
When a custom `BinaryType` is configured (other than the default `#!cpp std::vector<std::uint8_t>`), you can assign
values of that type directly to a `basic_json` instance, and they will automatically be recognized as binary values
@@ -89,12 +89,12 @@ assert(extracted == data);
This automatic type detection is a convenience feature that only applies to custom (non-default) `BinaryType` configurations.
The default `nlohmann::json` continues to treat `#!cpp std::vector<std::uint8_t>` as arrays for backward compatibility.
#### Storage
### Storage
Binary Arrays are stored as pointers in a `basic_json` type. That is, for any access to array values, a pointer of the
type `#!cpp binary_t*` must be dereferenced.
#### Notes on subtypes
### Notes on subtypes
- CBOR
- Binary values are represented as byte strings. Subtypes are written as tags.
+6 -2
View File
@@ -21,11 +21,11 @@ To store boolean values in C++, a type is defined by the template parameter `Bo
## Notes
#### Default type
### Default type
With the default values for `BooleanType` (`#!cpp bool`), the default value for `boolean_t` is `#!cpp bool`.
#### Storage
### Storage
Boolean values are stored directly inside a `basic_json` type.
@@ -45,6 +45,10 @@ Boolean values are stored directly inside a `basic_json` type.
--8<-- "examples/boolean_t.output"
```
## See also
- [is_boolean](is_boolean.md) checks whether the JSON value is a boolean
## Version history
- Added in version 1.0.0.
@@ -36,6 +36,13 @@ Constant.
--8<-- "examples/cbegin.output"
```
## See also
- [begin](begin.md) returns an iterator to the first element
- [cend](cend.md) returns a const iterator to one past the last element
- [crbegin](crbegin.md) returns a const reverse iterator to the last element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
- Added in version 1.0.0.
@@ -38,6 +38,12 @@ store
--8<-- "examples/cbor_tag_handler_t.output"
```
## See also
- [from_cbor](from_cbor.md) deserializes a JSON value from CBOR
- [input_format_t](input_format_t.md) the enumeration of supported input formats
- [CBOR](../../features/binary_formats/cbor.md) - the article on the CBOR format
## Version history
- Added in version 3.9.0. Added value `store` in 3.10.0.
+7
View File
@@ -36,6 +36,13 @@ Constant.
--8<-- "examples/cend.output"
```
## See also
- [end](end.md) returns an iterator to one past the last element
- [cbegin](cbegin.md) returns a const iterator to the first element
- [crend](crend.md) returns a const reverse iterator to one before the first element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
- Added in version 1.0.0.
+5
View File
@@ -52,6 +52,11 @@ All iterators, pointers, and references related to this container are invalidate
--8<-- "examples/clear.output"
```
## See also
- [erase](erase.md) removes elements from a JSON value
- [empty](empty.md) checks whether the JSON value has no elements
## Version history
- Added in version 1.0.0.
@@ -63,6 +63,18 @@ Logarithmic in the size of the JSON object.
If `#!cpp j.contains(x)` returns `#!c true` for a key or JSON pointer `x`, then it is safe to call `j[x]`.
!!! warning "Deprecation"
Overload (3) also accepts a [`json_pointer`](../json_pointer/index.md) whose template argument is a `basic_json`
specialization (e.g., `nlohmann::json_pointer<nlohmann::json>`) instead of a string type. This is deprecated since
version 3.11.0 and will be removed in a future major version; use `basic_json::json_pointer` (for `json`,
`nlohmann::json_pointer<std::string>`) instead.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#json-pointers) for how to update existing code.
## Examples
??? example "Example: (1) check with key"
@@ -36,6 +36,13 @@ Constant.
--8<-- "examples/crbegin.output"
```
## See also
- [crend](crend.md) returns a const reverse iterator to one before the first element
- [rbegin](rbegin.md) returns a reverse iterator to the last element
- [cbegin](cbegin.md) returns a const iterator to the first element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
- Added in version 1.0.0.
+7
View File
@@ -37,6 +37,13 @@ Constant.
--8<-- "examples/crend.output"
```
## See also
- [crbegin](crbegin.md) returns a const reverse iterator to the last element
- [rend](rend.md) returns a reverse iterator to one before the first element
- [cend](cend.md) returns a const iterator to one past the last element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
- Added in version 1.0.0.
@@ -30,6 +30,11 @@ The actual comparator used depends on [`object_t`](object_t.md) and can be obtai
--8<-- "examples/default_object_comparator_t.output"
```
## See also
- [object_comparator_t](object_comparator_t.md) the comparator actually used by `object_t`
- [object_t](object_t.md) the type used to store JSON objects
## Version history
- Added in version 3.11.0.
+2 -1
View File
@@ -31,7 +31,8 @@ a `#!cpp bool` denoting whether the insertion took place.
## Exception safety
Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
Strong guarantee: if an exception is thrown, there are no changes to any JSON value. As an exception, a `#!json null`
value is converted to an empty object before the element is added and keeps that type if adding the element throws.
## Exceptions
@@ -28,6 +28,11 @@ iterator is invalidated.
reference to the inserted element
## Exception safety
Strong guarantee: if an exception is thrown, there are no changes to any JSON value. As an exception, a `#!json null`
value is converted to an empty array before the element is added and keeps that type if adding the element throws.
## Exceptions
Throws [`type_error.311`](../../home/exceptions.md#jsonexceptiontype_error311) when called on a type other than JSON
+5
View File
@@ -60,6 +60,11 @@ itself is empty which is `#!cpp false` in the case of a string.
--8<-- "examples/empty.output"
```
## See also
- [size](size.md) returns the number of elements
- [clear](clear.md) clears the content and resets the value to the default value
## Version history
- Added in version 1.0.0.
+7
View File
@@ -37,6 +37,13 @@ Constant.
--8<-- "examples/end.output"
```
## See also
- [begin](begin.md) returns an iterator to the first element
- [cend](cend.md) returns a const iterator to one past the last element
- [rend](rend.md) returns a reverse iterator to one before the first element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
- Added in version 1.0.0.
@@ -37,6 +37,11 @@ ignore
--8<-- "examples/error_handler_t.output"
```
## See also
- [dump](dump.md) serializes a JSON value, with an `error_handler_t` parameter to configure invalid UTF-8 handling
- [Handling invalid UTF-8](../../features/serialization.md#handling-invalid-utf-8) - the article on handling invalid UTF-8
## Version history
- Added in version 3.4.0.
+16 -1
View File
@@ -27,7 +27,7 @@ Empty objects and arrays are flattened to `#!json null` and will not be reconstr
## Examples
??? example
??? example "Example: flatten a JSON object"
The following code shows how a JSON object is flattened to an object whose keys consist of JSON pointers.
@@ -41,6 +41,21 @@ Empty objects and arrays are flattened to `#!json null` and will not be reconstr
--8<-- "examples/flatten.output"
```
??? example "Example: empty objects and arrays are flattened to `#!json null`"
The following code shows that an empty object and an empty array are both flattened to `#!json null`, and that
`unflatten()` restores them as `#!json null` rather than as empty containers.
```cpp
--8<-- "examples/flatten__empty.cpp"
```
Output:
```json
--8<-- "examples/flatten__empty.output"
```
## See also
- [unflatten](unflatten.md) the reverse function
@@ -123,3 +123,5 @@ Linear in the size of the input.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#parsing) for how to update existing code.
@@ -133,3 +133,5 @@ Linear in the size of the input.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#parsing) for how to update existing code.
@@ -125,3 +125,5 @@ Linear in the size of the input.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#parsing) for how to update existing code.
@@ -124,3 +124,5 @@ Linear in the size of the input.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#parsing) for how to update existing code.
+26 -6
View File
@@ -13,16 +13,16 @@ BasicJsonType get() const;
// (3)
template<typename PointerType>
PointerType get_ptr();
PointerType get() noexcept;
template<typename PointerType>
constexpr const PointerType get_ptr() const noexcept;
const PointerType get() const noexcept; // constexpr since C++14
```
1. Explicit type conversion between the JSON value and a compatible value which is
[CopyConstructible](https://en.cppreference.com/w/cpp/named_req/CopyConstructible) and
[DefaultConstructible](https://en.cppreference.com/w/cpp/named_req/DefaultConstructible). The value is converted by
calling the `json_serializer<ValueType>` `from_json()` method.
calling the [`json_serializer<ValueType>`](json_serializer.md) `from_json()` method.
The function is equivalent to executing
```cpp
@@ -84,6 +84,12 @@ constexpr const PointerType get_ptr() const noexcept;
3. pointer to the internally stored JSON value if the requested pointer type fits to the JSON value; `#!cpp nullptr`
otherwise
## Exception safety
Depends on what `json_serializer<ValueType>` `from_json()` method throws for overloads (1) and (2); the JSON value
itself is never modified, since `get()` is a `#!cpp const` member function. No-throw guarantee for overload (3): this
function never throws exceptions.
## Exceptions
Depends on what `json_serializer<ValueType>` `from_json()` method throws
@@ -123,13 +129,13 @@ overload (3).
## Examples
??? example
??? example "Example: (1) explicit conversion to compatible types"
The example below shows several conversions from JSON values
to other types. There a few things to note: (1) Floating-point numbers can
be converted to integers, (2) A JSON array can be converted to a standard
`std::vector<short>`, (3) A JSON object can be converted to C++
associative containers such as `std::unordered_map<std::string, json>`.
associative containers such as `std::map<std::string, json>`.
```cpp
--8<-- "examples/get__ValueType_const.cpp"
@@ -141,7 +147,21 @@ overload (3).
--8<-- "examples/get__ValueType_const.output"
```
??? example
??? example "Example: (2) explicit conversion to another `basic_json` specialization"
The example below shows how a `json` value is converted to an `ordered_json` value using `get<BasicJsonType>()`.
```cpp
--8<-- "examples/get__BasicJsonType.cpp"
```
Output:
```json
--8<-- "examples/get__BasicJsonType.output"
```
??? example "Example: (3) explicit pointer access to the stored value"
The example below shows how pointers to internal values of a JSON value can be requested. Note that no type
conversions are made and a `#cpp nullptr` is returned if the value and the requested pointer type does not match.
@@ -10,6 +10,14 @@ Returns the allocator associated with the container.
associated allocator
## Exception safety
Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
## Complexity
Constant.
## Examples
??? example
@@ -26,6 +34,11 @@ associated allocator
--8<-- "examples/get_allocator.output"
```
## See also
- [basic_json](index.md#template-parameters) the class template, with `AllocatorType` as one of its template parameters
- [Template Parameter Requirements](../../features/types/template_parameters.md#allocatortype) - the requirements for `AllocatorType`
## Version history
- Added in version 1.0.0.
+7 -2
View File
@@ -8,7 +8,7 @@ ValueType& get_to(ValueType& v) const noexcept(
```
Explicit type conversion between the JSON value and a compatible value. The value is filled into the input parameter by
calling the `json_serializer<ValueType>` `from_json()` method.
calling the [`json_serializer<ValueType>`](json_serializer.md) `from_json()` method.
The function is equivalent to executing
```cpp
@@ -34,6 +34,11 @@ the compiler reports that no matching `get_to` was found.
the input parameter, allowing chaining calls
## Exception safety
Depends on what `json_serializer<ValueType>` `from_json()` method throws; the JSON value itself is never modified,
since `get_to()` is a `#!cpp const` member function.
## Exceptions
Depends on what `json_serializer<ValueType>` `from_json()` method throws
@@ -49,7 +54,7 @@ Depends on the `json_serializer<ValueType>::from_json()` implementation.
The example below shows several conversions from JSON values to other types. There a few things to note: (1)
Floating-point numbers can be converted to integers, (2) A JSON array can be converted to a standard
`#!cpp std::vector<short>`, (3) A JSON object can be converted to C++ associative containers such as
`#cpp std::unordered_map<std::string, json>`.
`#!cpp std::map<std::string, json>`.
```cpp
--8<-- "examples/get_to.cpp"
@@ -51,6 +51,11 @@ bon8
--8<-- "examples/sax_parse__binary.output"
```
## See also
- [sax_parse](sax_parse.md) generic SAX parse interface, taking an `input_format_t` to select the input format
- [cbor_tag_handler_t](cbor_tag_handler_t.md) configures how CBOR tags are treated while parsing
## Version history
- Added in version 3.2.0.
+6 -6
View File
@@ -109,11 +109,11 @@ Strong exception safety: if an exception occurs, the original value stays intact
2. Linear in `cnt` plus linear in the distance between `pos` and end of the container.
3. Linear in `#!cpp std::distance(first, last)` plus linear in the distance between `pos` and end of the container.
4. Linear in `ilist.size()` plus linear in the distance between `pos` and end of the container.
5. Logarithmic: `O(N*log(size() + N))`, where `N` is the number of elements to insert.
5. `O(N*log(size() + N))`, where `N` is the number of elements to insert.
## Examples
??? example "Example (1): insert element into array"
??? example "Example: (1) insert element into array"
The example shows how `insert()` is used.
@@ -127,7 +127,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
--8<-- "examples/insert.output"
```
??? example "Example (2): insert copies of element into array"
??? example "Example: (2) insert copies of element into array"
The example shows how `insert()` is used.
@@ -141,7 +141,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
--8<-- "examples/insert__count.output"
```
??? example "Example (3): insert a range of elements into an array"
??? example "Example: (3) insert a range of elements into an array"
The example shows how `insert()` is used.
@@ -155,7 +155,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
--8<-- "examples/insert__range.output"
```
??? example "Example (4): insert elements from an initializer list into an array"
??? example "Example: (4) insert elements from an initializer list into an array"
The example shows how `insert()` is used.
@@ -169,7 +169,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
--8<-- "examples/insert__ilist.output"
```
??? example "Example (5): insert a range of elements into an object"
??? example "Example: (5) insert a range of elements into an object"
The example shows how `insert()` is used.
@@ -34,6 +34,13 @@ Constant.
--8<-- "examples/is_array.output"
```
## See also
- [is_object](is_object.md) checks whether the JSON value is an object
- [is_structured](is_structured.md) checks whether the JSON value is structured (array or object)
- [type](type.md) returns the type of the JSON value
- [array_t](array_t.md) the type used to store JSON arrays
## Version history
- Added in version 1.0.0.
@@ -34,6 +34,12 @@ Constant.
--8<-- "examples/is_binary.output"
```
## See also
- [is_primitive](is_primitive.md) checks whether the JSON value is primitive
- [binary_t](binary_t.md) the type used to store binary values
- [get_binary](get_binary.md) returns a reference to the stored binary value
## Version history
- Added in version 3.8.0.
@@ -34,6 +34,11 @@ Constant.
--8<-- "examples/is_boolean.output"
```
## See also
- [boolean_t](boolean_t.md) the type used to store JSON booleans
- [is_primitive](is_primitive.md) checks whether the JSON value is primitive
## Version history
- Added in version 1.0.0.
@@ -55,7 +55,7 @@ with `allow_exceptions` set to `#!cpp false`: a parse error then yields a discar
## Examples
??? example
??? example "Example: `is_discarded()` for ordinary JSON values"
The following code exemplifies `is_discarded()` for all JSON types.
@@ -69,6 +69,22 @@ with `allow_exceptions` set to `#!cpp false`: a parse error then yields a discar
--8<-- "examples/is_discarded.output"
```
??? example "Example: discarded values from parsing"
The following code shows the two situations in which a discarded value can be observed: parsing invalid JSON with
`allow_exceptions` set to `#!cpp false`, and a parser callback that discards the top-level value (which is replaced
by `#!json null` and therefore does *not* remain discarded).
```cpp
--8<-- "examples/is_discarded__parse.cpp"
```
Output:
```json
--8<-- "examples/is_discarded__parse.output"
```
## Version history
- Added in version 1.0.0.
@@ -34,6 +34,13 @@ Constant.
--8<-- "examples/is_null.output"
```
## See also
- [is_array](is_array.md) checks whether the JSON value is an array
- [is_object](is_object.md) checks whether the JSON value is an object
- [type](type.md) returns the type of the JSON value
- [value_t](value_t.md) the enumeration of JSON types
## Version history
- Added in version 1.0.0.
@@ -34,6 +34,13 @@ Constant.
--8<-- "examples/is_object.output"
```
## See also
- [is_array](is_array.md) checks whether the JSON value is an array
- [is_structured](is_structured.md) checks whether the JSON value is structured (array or object)
- [type](type.md) returns the type of the JSON value
- [object_t](object_t.md) the type used to store JSON objects
## Version history
- Added in version 1.0.0.
@@ -34,6 +34,12 @@ Constant.
--8<-- "examples/is_string.output"
```
## See also
- [is_primitive](is_primitive.md) checks whether the JSON value is primitive
- [type](type.md) returns the type of the JSON value
- [string_t](string_t.md) the type used to store JSON strings
## Version history
- Added in version 1.0.0.
+2
View File
@@ -114,3 +114,5 @@ When iterating over an array, `key()` will return the index of the element as st
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#miscellaneous-functions) for how to update existing code.
@@ -14,12 +14,12 @@ Examples of such functionality might be metadata, additional member functions (e
## Notes
#### Default type
### Default type
The default value for `CustomBaseClass` is `void`. In this case, an
[empty base class](https://en.cppreference.com/w/cpp/language/ebo) is used and no additional functionality is injected.
#### Limitations
### Limitations
The type `CustomBaseClass` has to be a default-constructible, non-`final` class.
`basic_json` only supports copy/move construction/assignment if `CustomBaseClass` does so as well.
@@ -43,6 +43,10 @@ A `CustomBaseClass` with non-static data members forfeits `basic_json`'s
--8<-- "examples/json_base_class_t.output"
```
## See also
- [Template Parameter Requirements](../../features/types/template_parameters.md#custombaseclass) - the requirements for `CustomBaseClass`
## Version history
- Added in version 3.12.0.
@@ -15,11 +15,11 @@ using json_serializer = JSONSerializer<T, SFINAE>;
## Notes
#### Default type
### Default type
The default values for `json_serializer` is [`adl_serializer`](../adl_serializer/index.md).
#### Requirements
### Requirements
A custom serializer must provide `#!cpp static void to_json(basic_json&, T)` for every type it serializes, and either
`#!cpp static void from_json(const basic_json&, T&)` or `#!cpp static T from_json(const basic_json&)` for every type it
@@ -42,6 +42,13 @@ deserializes. See [Template Parameter Requirements](../../features/types/templat
--8<-- "examples/from_json__non_default_constructible.output"
```
## See also
- [adl_serializer](../adl_serializer/index.md) the default `json_serializer`
- [get](get.md) explicit type conversion using the `json_serializer`'s `from_json()` method
- [get_to](get_to.md) explicit type conversion into a variable using the `json_serializer`'s `from_json()` method
- [Arbitrary Type Conversions](../../features/arbitrary_types.md) - the article on converting between JSON values and arbitrary types
## Version history
- Since version 2.0.0.
@@ -54,6 +54,12 @@ string elements the JSON value can store which is `1`.
Note the output is platform-dependent.
## See also
- [size](size.md) returns the number of elements
- [array_t](array_t.md) the type used to store JSON arrays
- [object_t](object_t.md) the type used to store JSON objects
## Version history
- Added in version 1.0.0.
@@ -33,6 +33,10 @@ Thereby, `Target` is the current object; that is, the patch is applied to the cu
`apply_patch` (in)
: the patch to apply
## Exception safety
Basic guarantee: if an exception is thrown during the operation, the JSON value may be partially modified.
## Complexity
Linear in the lengths of `apply_patch`.
@@ -32,18 +32,18 @@ type to use.
## Notes
#### Default type
### Default type
With the default values for `NumberFloatType` (`double`), the default value for `number_float_t` is `#!cpp double`.
#### Default behavior
### Default behavior
- The restrictions about leading zeros are not enforced in C++. Instead, leading zeros in floating-point literals will
be ignored. Internally, the value will be stored as a decimal number. For instance, the C++ floating-point literal
`01.2` will be serialized to `1.2`. During deserialization, leading zeros yield an error.
- Not-a-number (NaN) values will be serialized to `null`.
#### Limits
### Limits
[RFC 8259](https://tools.ietf.org/html/rfc8259) states:
> This specification allows implementations to set limits on the range and precision of numbers accepted. Since software
@@ -55,7 +55,7 @@ This implementation does exactly follow this approach, as it uses double precisi
smaller than `-1.79769313486232e+308` and values greater than `1.79769313486232e+308` will be stored as NaN internally
and be serialized to `null`.
#### Storage
### Storage
Floating-point number values are stored directly inside a `basic_json` type.
@@ -75,6 +75,13 @@ Floating-point number values are stored directly inside a `basic_json` type.
--8<-- "examples/number_float_t.output"
```
## See also
- [number_integer_t](number_integer_t.md) the type used to store JSON integer numbers
- [number_unsigned_t](number_unsigned_t.md) the type used to store JSON unsigned integer numbers
- [is_number_float](is_number_float.md) checks whether the JSON value is a floating-point number
- [Number Handling](../../features/types/number_handling.md) - the article on number handling
## Version history
- Added in version 1.0.0.
@@ -29,18 +29,18 @@ to use.
## Notes
#### Default type
### Default type
With the default values for `NumberIntegerType` (`std::int64_t`), the default value for `number_integer_t` is
`#!cpp std::int64_t`.
#### Default behavior
### Default behavior
- The restrictions about leading zeros are not enforced in C++. Instead, leading zeros in integer literals lead to an
interpretation as an octal number. Internally, the value will be stored as a decimal number. For instance, the C++
integer literal `010` will be serialized to `8`. During deserialization, leading zeros yield an error.
#### Limits
### Limits
[RFC 8259](https://tools.ietf.org/html/rfc8259) specifies:
> An implementation may set limits on the range and precision of numbers.
@@ -57,7 +57,7 @@ will automatically be stored as [`number_unsigned_t`](number_unsigned_t.md) or [
As this range is a subrange of the exactly supported range [INT64_MIN, INT64_MAX], this class's integer type is
interoperable.
#### Storage
### Storage
Integer number values are stored directly inside a `basic_json` type.
@@ -77,6 +77,13 @@ Integer number values are stored directly inside a `basic_json` type.
--8<-- "examples/number_integer_t.output"
```
## See also
- [number_unsigned_t](number_unsigned_t.md) the type used to store JSON unsigned integer numbers
- [number_float_t](number_float_t.md) the type used to store JSON floating-point numbers
- [is_number_integer](is_number_integer.md) checks whether the JSON value is a signed integer number
- [Number Handling](../../features/types/number_handling.md) - the article on number handling
## Version history
- Added in version 1.0.0.
@@ -30,18 +30,18 @@ the type to use.
## Notes
#### Default type
### Default type
With the default values for `NumberUnsignedType` (`std::uint64_t`), the default value for `number_unsigned_t` is
`#!cpp std::uint64_t`.
#### Default behavior
### Default behavior
- The restrictions about leading zeros are not enforced in C++. Instead, leading zeros in integer literals lead to an
interpretation as an octal number. Internally, the value will be stored as a decimal number. For instance, the C++
integer literal `010` will be serialized to `8`. During deserialization, leading zeros yield an error.
#### Limits
### Limits
[RFC 8259](https://tools.ietf.org/html/rfc8259) specifies:
> An implementation may set limits on the range and precision of numbers.
@@ -58,7 +58,7 @@ as [`number_integer_t`](number_integer_t.md) or [`number_float_t`](number_float_
As this range is a subrange (when considered in conjunction with the `number_integer_t` type) of the exactly supported
range [0, UINT64_MAX], this class's integer type is interoperable.
#### Storage
### Storage
Integer number values are stored directly inside a `basic_json` type.
@@ -78,6 +78,13 @@ Integer number values are stored directly inside a `basic_json` type.
--8<-- "examples/number_unsigned_t.output"
```
## See also
- [number_integer_t](number_integer_t.md) the type used to store JSON integer numbers
- [number_float_t](number_float_t.md) the type used to store JSON floating-point numbers
- [is_number_unsigned](is_number_unsigned.md) checks whether the JSON value is an unsigned integer number
- [Number Handling](../../features/types/number_handling.md) - the article on number handling
## Version history
- Added in version 2.0.0.
@@ -25,6 +25,11 @@ and [`default_object_comparator_t`](default_object_comparator_t.md) otherwise.
--8<-- "examples/object_comparator_t.output"
```
## See also
- [object_t](object_t.md) the type used to store JSON objects
- [default_object_comparator_t](default_object_comparator_t.md) the fallback comparator used when `object_t` has no `key_compare` member type
## Version history
- Added in version 3.0.0.
+14 -7
View File
@@ -33,7 +33,7 @@ To store objects in C++, a type is defined by the template parameters described
## Notes
#### Default type
### Default type
With the default values for `ObjectType` (`std::map`), `StringType` (`std::string`), and `AllocatorType`
(`std::allocator`), the default value for `object_t` is:
@@ -58,7 +58,7 @@ std::map<
See [`default_object_comparator_t`](default_object_comparator_t.md) for more information.
#### Behavior
### Behavior
The choice of `object_t` influences the behavior of the JSON class. With the default type, objects have the following
behavior:
@@ -76,7 +76,7 @@ behavior:
that they will not be affected by these differences. For instance, `#!json {"b": 1, "a": 2}` and
`#!json {"a": 2, "b": 1}` will be treated as equal.
#### Limits
### Limits
[RFC 8259](https://tools.ietf.org/html/rfc8259) specifies:
> An implementation may set limits on the maximum depth of nesting.
@@ -85,12 +85,12 @@ In this class, the object's limit of nesting is not explicitly constrained. Howe
introduced by the compiler or runtime environment. A theoretical limit can be queried by calling the
[`max_size`](max_size.md) function of a JSON object.
#### Storage
### Storage
Objects are stored as pointers in a `basic_json` type. That is, for any access to object values, a pointer of type
`object_t*` must be dereferenced.
#### Object key order
### Object key order
The order name/value pairs are added to the object are *not* preserved by the library. Therefore, iterating an object
may return name/value pairs in a different order than they were originally stored. In fact, keys will be traversed in
@@ -98,10 +98,10 @@ alphabetical order as `std::map` with `std::less` is used by default. Please not
[RFC 8259](https://tools.ietf.org/html/rfc8259), because any order implements the specified "unordered" nature of JSON
objects.
#### Cross-`basic_json` conversion requirements
### Cross-`basic_json` conversion requirements
When converting an object from one `basic_json` specialization to another via the
[converting constructor](basic_json.md#overload-4), the target `object_t`'s `key_type` must be
[converting constructor](basic_json.md) (overload 4), the target `object_t`'s `key_type` must be
directly constructible from the source `basic_json`'s `string_t` type (or more generally, from the
source object's key type). If this requirement is not met, the conversion does not fail; instead,
the object is silently converted as an array of key-value pairs, which is incorrect. See
@@ -123,6 +123,13 @@ the object is silently converted as an array of key-value pairs, which is incorr
--8<-- "examples/object_t.output"
```
## See also
- [array_t](array_t.md) the type used to store JSON arrays
- [string_t](string_t.md) the type used to store JSON strings
- [object_comparator_t](object_comparator_t.md) the comparator used to order object keys
- [Object Order](../../features/object_order.md) - the article on object key ordering
## Version history
- Added in version 1.0.0.
@@ -48,6 +48,12 @@ invalidates all iterators and all references.
`#!cpp *this`
## Exception safety
Strong guarantee: if an exception is thrown, there are no changes to any JSON value. As an exception, a `#!json null`
value is converted to an empty array or object before the element is added and keeps that type if adding the element
throws.
## Exceptions
1. Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
@@ -133,6 +133,18 @@ Strong exception safety: if an exception occurs, the original value stays intact
while `/foo/one/one/one` creates nested objects. This is not specified by the JSON Pointer RFC; it is
this library's own, intentional disambiguation rule. See also [JSON Pointer](../../features/json_pointer.md).
!!! warning "Deprecation"
Overload (4) also accepts a [`json_pointer`](../json_pointer/index.md) whose template argument is a `basic_json`
specialization (e.g., `nlohmann::json_pointer<nlohmann::json>`) instead of a string type. This is deprecated since
version 3.11.0 and will be removed in a future major version; use `basic_json::json_pointer` (for `json`,
`nlohmann::json_pointer<std::string>`) instead.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#json-pointers) for how to update existing code.
## Examples
??? example "Example: (1) access specified array element"
@@ -17,6 +17,11 @@ Implicit type conversion between the JSON value and a compatible value. The call
copy of the JSON value, converted to `ValueType`
## Exception safety
Depends on what `json_serializer<ValueType>` `from_json()` method throws; the JSON value itself is never modified,
since `#!cpp operator ValueType()` is a `#!cpp const` member function that only calls [`get()`](get.md).
## Exceptions
Depends on what `json_serializer<ValueType>` `from_json()` method throws
@@ -56,6 +61,8 @@ Linear in the size of the JSON value.
[`JSON_USE_IMPLICIT_CONVERSIONS`](../macros/json_use_implicit_conversions.md) to `0` and replace any implicit
conversions with calls to [`get`](../basic_json/get.md).
See the [migration guide](../../integration/migration_guide.md#replace-implicit-conversions) for how to update existing code.
## Examples
??? example
@@ -63,7 +70,7 @@ Linear in the size of the JSON value.
The example below shows several conversions from JSON values to other types. There are a few things to note: (1)
Floating-point numbers can be converted to integers, (2) A JSON array can be converted to a standard
`std::vector<short>`, (3) A JSON object can be converted to C++ associative containers such as
`std::unordered_map<std::string, json>`.
`std::map<std::string, json>`.
```cpp
--8<-- "examples/operator__ValueType.cpp"
@@ -134,7 +134,7 @@ Linear.
## Examples
??? example
??? example "Example: (1) compare JSON values"
The example demonstrates comparing several JSON types.
@@ -148,7 +148,7 @@ Linear.
--8<-- "examples/operator__equal.output"
```
??? example
??? example "Example: (2) compare JSON values with `#!cpp nullptr`"
The example demonstrates comparing several JSON types against the null pointer (JSON `#!json null`).
@@ -60,6 +60,16 @@ Linear.
Since C++20 overload resolution will consider the _rewritten candidate_ generated from
[`operator<=>`](operator_spaceship.md).
!!! warning "Deprecation"
If [`JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](../macros/json_use_legacy_discarded_value_comparison.md) is
defined to `1`, the library declares a member `#!cpp bool operator>=(const_reference rhs) const noexcept` in
C++20 mode to emulate the legacy comparison of discarded values. This member is deprecated since version 3.11.0,
together with the legacy comparison behavior.
See the [migration guide](../../integration/migration_guide.md#miscellaneous-functions) for how to update existing
code.
## Examples
??? example
@@ -61,6 +61,16 @@ Linear.
Since C++20 overload resolution will consider the _rewritten candidate_ generated from
[`operator<=>`](operator_spaceship.md).
!!! warning "Deprecation"
If [`JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](../macros/json_use_legacy_discarded_value_comparison.md) is
defined to `1`, the library declares a member `#!cpp bool operator<=(const_reference rhs) const noexcept` in
C++20 mode to emulate the legacy comparison of discarded values. This member is deprecated since version 3.11.0,
together with the legacy comparison behavior.
See the [migration guide](../../integration/migration_guide.md#miscellaneous-functions) for how to update existing
code.
## Examples
??? example
+18 -15
View File
@@ -9,17 +9,9 @@ bool operator!=(const_reference lhs, const ScalarType rhs) noexcept; // (2)
template<typename ScalarType>
bool operator!=(ScalarType lhs, const const_reference rhs) noexcept; // (2)
// since C++20
class basic_json {
bool operator!=(const_reference rhs) const noexcept; // (1)
template<typename ScalarType>
bool operator!=(ScalarType rhs) const noexcept; // (2)
};
```
1. Compares two JSON values for inequality. Returns `#!cpp !(lhs == rhs)` (until C++20) or `#!cpp !(*this == rhs)` (since C++20).
1. Compares two JSON values for inequality. Returns `#!cpp !(lhs == rhs)`.
- This means the comparison is simply the logical negation of `operator==`, including for special values like `NaN` and `discarded`.
2. Compares a JSON value and a scalar or a scalar and a JSON value for inequality by converting the scalar to a JSON
@@ -52,6 +44,11 @@ Linear.
## Notes
!!! note "C++20"
Since C++20, `basic_json` declares no `operator!=`. The compiler rewrites `#!cpp a != b` as `#!cpp !(a == b)`
using [`operator==`](operator_eq.md), so the result is the same as described above.
!!! note "Comparing `NaN` and `discarded`"
Since `operator!=` is defined as `!(a == b)`, the behavior for special values follows that of `operator==`:
@@ -61,7 +58,7 @@ Linear.
## Examples
??? example
??? example "Example: (1) compare JSON values"
The example demonstrates comparing several JSON types.
@@ -75,7 +72,7 @@ Linear.
--8<-- "examples/operator__notequal.output"
```
??? example
??? example "Example: (2) compare JSON values with `#!cpp nullptr`"
The example demonstrates comparing several JSON types against the null pointer (JSON `#!json null`).
@@ -89,9 +86,15 @@ Linear.
--8<-- "examples/operator__notequal__nullptr_t.output"
```
## See also
- [operator==](operator_eq.md) comparison: equal
- [operator<=>](operator_spaceship.md) comparison: 3-way (C++20)
## Version history
1. Added in version 1.0.0. Added C++20 member functions in version 3.11.0. Changed in version 3.13.0 to remove
special-casing for `NaN` and `discarded` values; `operator!=` now consistently means `!(a == b)`.
2. Added in version 1.0.0. Added C++20 member functions in version 3.11.0. Changed in version 3.13.0 to remove
special-casing for `NaN` and `discarded` values; `operator!=` now consistently means `!(a == b)`.
1. Added in version 1.0.0. Added a C++20 member function in version 3.11.0. Changed in version 3.13.0 to remove
special-casing for `NaN` and `discarded` values; `operator!=` now consistently means `!(a == b)`. Removed the C++20
member function in version 3.13.0; since C++20, the compiler rewrites `a != b` using `operator==`.
2. Added in version 1.0.0. Changed in version 3.13.0 to remove special-casing for `NaN` and `discarded` values;
`operator!=` now consistently means `!(a == b)`. Since C++20, the compiler rewrites `a != b` using `operator==`.
@@ -47,6 +47,11 @@ Constant.
--8<-- "examples/operator__value_t.output"
```
## See also
- [type](type.md) named member function equivalent to this implicit conversion operator
- [value_t](value_t.md) the enumeration of JSON types
## Version history
- Added in version 1.0.0.
+11 -9
View File
@@ -109,7 +109,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
## Examples
??? example "Parsing from a character array"
??? example "Example: (1) parse from a character array"
The example below demonstrates the `parse()` function reading from an array.
@@ -123,7 +123,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/parse__array__parser_callback_t.output"
```
??? example "Parsing from a string"
??? example "Example: (1) parse from a string"
The example below demonstrates the `parse()` function with and without callback function.
@@ -137,7 +137,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/parse__string__parser_callback_t.output"
```
??? example "Parsing from an input stream"
??? example "Example: (1) parse from an input stream"
The example below demonstrates the `parse()` function with and without callback function.
@@ -151,7 +151,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/parse__istream__parser_callback_t.output"
```
??? example "Parsing from a contiguous container"
??? example "Example: (1) parse from a contiguous container"
The example below demonstrates the `parse()` function reading from a contiguous container.
@@ -165,7 +165,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/parse__contiguouscontainer__parser_callback_t.output"
```
??? example "Parsing from a non-null-terminated string"
??? example "Example: (2) parse from a non-null-terminated string"
The example below demonstrates the `parse()` function reading from a string that is not null-terminated.
@@ -179,7 +179,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/parse__pointers.output"
```
??? example "Parsing from an iterator pair"
??? example "Example: (2) parse from an iterator pair"
The example below demonstrates the `parse()` function reading from an iterator pair.
@@ -193,7 +193,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/parse__iterator_pair.output"
```
??? example "Effect of `allow_exceptions` parameter"
??? example "Example: effect of `allow_exceptions` parameter"
The example below demonstrates the effect of the `allow_exceptions` parameter in the `parse()` function.
@@ -207,7 +207,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/parse__allow_exceptions.output"
```
??? example "Effect of `ignore_comments` parameter"
??? example "Example: effect of `ignore_comments` parameter"
The example below demonstrates the effect of the `ignore_comments` parameter in the `parse()` function.
@@ -221,7 +221,7 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/comments.output"
```
??? example "Effect of `ignore_trailing_commas` parameter"
??? example "Example: effect of `ignore_trailing_commas` parameter"
The example below demonstrates the effect of the `ignore_trailing_commas` parameter in the `parse()` function.
@@ -263,3 +263,5 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#parsing) for how to update existing code.
@@ -24,6 +24,21 @@ The parser callback distinguishes the following events:
![Example when certain parse events are triggered](../../images/callback_events.png)
??? example
The following code parses a small JSON text with a parser callback that reports every event together with its
depth and keeps every value (by always returning `#!cpp true`).
```cpp
--8<-- "examples/parse_event_t.cpp"
```
Output:
```json
--8<-- "examples/parse_event_t.output"
```
## See also
- [parser_callback_t](parser_callback_t.md) callback function type for the parser
@@ -60,7 +60,7 @@ the latter case, it is skipped completely, or replaced by `null` if it is the to
## Examples
??? example
??? example "Example: skip an object key while parsing"
The example below demonstrates the `parse()` function with
and without callback function.
@@ -75,7 +75,7 @@ the latter case, it is skipped completely, or replaced by `null` if it is the to
--8<-- "examples/parse__string__parser_callback_t.output"
```
??? example
??? example "Example: how discarded values are removed"
The example below shows where discarded values are removed. The array and the number are discarded in different
ways, but in each case the parse result contains neither the value nor its key.
+31 -2
View File
@@ -26,10 +26,24 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [`parse_error.104`](../../home/exceptions.md#jsonexceptionparse_error104) if the JSON patch does not consist of
an array of objects.
- Throws [`parse_error.105`](../../home/exceptions.md#jsonexceptionparse_error105) if the JSON patch is malformed (e.g.,
mandatory attributes are missing); example: `"operation add must have member path"`.
mandatory attributes are missing); example: `"operation 'add' must have member 'path'"`.
- Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if an array index is out of range.
- Throws [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) if an array index in a "path" or
"from" member begins with '0'; example: `"array index '01' must not begin with '0'"`.
- Throws [`parse_error.107`](../../home/exceptions.md#jsonexceptionparse_error107) if a "path" or "from" member is not
empty and does not begin with a slash (`/`); example: `"JSON pointer must be empty or begin with '/' - was: 'a'"`.
- Throws [`parse_error.108`](../../home/exceptions.md#jsonexceptionparse_error108) if a tilde (`~`) in a "path" or
"from" member is not followed by `0` or `1`; example: `"escape character '~' must be followed with '0' or '1'"`.
- Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) if an array index in a "path" or
"from" member is not a number; example: `"array index 'foo' is not a number"`.
- Throws [`out_of_range.402`](../../home/exceptions.md#jsonexceptionout_of_range402) if the array index `-` is used
where an existing element is required (the "path" of "replace", the "from" of "move" and "copy"); example:
`"array index '-' (3) is out of range"`.
- Throws [`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403) if a JSON pointer inside the patch
could not be resolved successfully in the current JSON value; example: `"key baz not found"`.
- Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if a reference token of a JSON
pointer inside the patch cannot be resolved, e.g., `-` in a "remove" operation or `1a` for an array; example:
`"unresolved reference token '-'"`.
- Throws [`out_of_range.405`](../../home/exceptions.md#jsonexceptionout_of_range405) if JSON pointer has no parent
("add", "remove", "move")
- Throws [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) if an "add" operation's target
@@ -53,7 +67,7 @@ is thrown. In any case, the original value is not changed: the patch is applied
## Examples
??? example
??? example "Example: apply a JSON patch"
The following code shows how a JSON patch is applied to a value.
@@ -67,6 +81,21 @@ is thrown. In any case, the original value is not changed: the patch is applied
--8<-- "examples/patch.output"
```
??? example "Example: out_of_range.414 exception"
The following code shows how a "move" operation whose "from" location is a proper prefix of its "path" location is
rejected, and how the original document is left unchanged because the patch is applied to a copy.
```cpp
--8<-- "examples/patch__exception.cpp"
```
Output:
```json
--8<-- "examples/patch__exception.output"
```
## See also
- [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
@@ -22,10 +22,24 @@ No guarantees, value may be corrupted by an unsuccessful patch operation.
- Throws [`parse_error.104`](../../home/exceptions.md#jsonexceptionparse_error104) if the JSON patch does not consist of
an array of objects.
- Throws [`parse_error.105`](../../home/exceptions.md#jsonexceptionparse_error105) if the JSON patch is malformed (e.g.,
mandatory attributes are missing); example: `"operation add must have member path"`.
mandatory attributes are missing); example: `"operation 'add' must have member 'path'"`.
- Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if an array index is out of range.
- Throws [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) if an array index in a "path" or
"from" member begins with '0'; example: `"array index '01' must not begin with '0'"`.
- Throws [`parse_error.107`](../../home/exceptions.md#jsonexceptionparse_error107) if a "path" or "from" member is not
empty and does not begin with a slash (`/`); example: `"JSON pointer must be empty or begin with '/' - was: 'a'"`.
- Throws [`parse_error.108`](../../home/exceptions.md#jsonexceptionparse_error108) if a tilde (`~`) in a "path" or
"from" member is not followed by `0` or `1`; example: `"escape character '~' must be followed with '0' or '1'"`.
- Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) if an array index in a "path" or
"from" member is not a number; example: `"array index 'foo' is not a number"`.
- Throws [`out_of_range.402`](../../home/exceptions.md#jsonexceptionout_of_range402) if the array index `-` is used
where an existing element is required (the "path" of "replace", the "from" of "move" and "copy"); example:
`"array index '-' (3) is out of range"`.
- Throws [`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403) if a JSON pointer inside the patch
could not be resolved successfully in the current JSON value; example: `"key baz not found"`.
- Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if a reference token of a JSON
pointer inside the patch cannot be resolved, e.g., `-` in a "remove" operation or `1a` for an array; example:
`"unresolved reference token '-'"`.
- Throws [`out_of_range.405`](../../home/exceptions.md#jsonexceptionout_of_range405) if JSON pointer has no parent
("add", "remove", "move")
- Throws [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) if an "add" operation's target
@@ -50,7 +64,7 @@ function throws an exception.
## Examples
??? example
??? example "Example: apply a JSON patch in place"
The following code shows how a JSON patch is applied to a value.
@@ -64,6 +78,22 @@ function throws an exception.
--8<-- "examples/patch_inplace.output"
```
??? example "Example: out_of_range.403 exception with a partially applied patch"
The following code shows a patch whose first operation succeeds and whose second operation fails. Because
`patch_inplace` applies each operation directly to the value, the first operation's effect is still visible after
the exception is caught, unlike [`patch`](patch.md).
```cpp
--8<-- "examples/patch_inplace__exception.cpp"
```
Output:
```json
--8<-- "examples/patch_inplace__exception.output"
```
## See also
- [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
@@ -44,6 +44,12 @@ invalidates all iterators and all references.
`init` (in)
: an initializer list
## Exception safety
Strong guarantee: if an exception is thrown, there are no changes to any JSON value. As an exception, a `#!json null`
value is converted to an empty array or object before the element is added and keeps that type if adding the element
throws.
## Exceptions
1. Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) when called on a type other than
@@ -37,6 +37,13 @@ Constant.
--8<-- "examples/rbegin.output"
```
## See also
- [rend](rend.md) returns a reverse iterator to one before the first element
- [crbegin](crbegin.md) returns a const reverse iterator to the last element
- [begin](begin.md) returns an iterator to the first element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
- Added in version 1.0.0.
+7
View File
@@ -38,6 +38,13 @@ Constant.
--8<-- "examples/rend.output"
```
## See also
- [rbegin](rbegin.md) returns a reverse iterator to the last element
- [crend](crend.md) returns a const reverse iterator to one before the first element
- [end](end.md) returns an iterator to one past the last element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
- Added in version 1.0.0.
@@ -147,3 +147,5 @@ A UTF-8 byte order mark is silently ignored.
Overload (2) replaces calls to `sax_parse` with a pair of iterators as their first parameter which has been
deprecated in version 3.8.0. This overload will be removed in version 4.0.0. Please replace all calls like
`#!cpp sax_parse({ptr, ptr+len});` with `#!cpp sax_parse(ptr, ptr+len);`.
See the [migration guide](../../integration/migration_guide.md#parsing) for how to update existing code.
+5
View File
@@ -51,6 +51,11 @@ JSON value which is `1` in the case of a string.
--8<-- "examples/size.output"
```
## See also
- [empty](empty.md) checks whether the JSON value has no elements
- [max_size](max_size.md) returns the maximum possible number of elements
## Version history
- Added in version 1.0.0.
@@ -28,6 +28,10 @@ type of the JSON value is taken into account to have different hash values for `
Note the output is platform-dependent.
## See also
- [operator==](operator_eq.md) compares two JSON values for equality, consistent with equal hash values
## Version history
- Added in version 1.0.0.
+12 -6
View File
@@ -30,16 +30,16 @@ JSON class into byte-sized characters during deserialization.
## Notes
#### Default type
### Default type
With the default values for `StringType` (`std::string`), the default value for `string_t` is `#!cpp std::string`.
#### Encoding
### Encoding
Strings are stored in UTF-8 encoding. Therefore, functions like `std::string::size()` or `std::string::length()` return
the number of bytes in the string rather than the number of characters or glyphs.
#### String comparison
### String comparison
[RFC 8259](https://tools.ietf.org/html/rfc8259) states:
> Software implementations are typically required to test names of object members for equality. Implementations that
@@ -50,15 +50,15 @@ the number of bytes in the string rather than the number of characters or glyphs
This implementation is interoperable as it does compare strings code unit by code unit.
#### Storage
### Storage
String values are stored as pointers in a `basic_json` type. That is, for any access to string values, a pointer of type
`string_t*` must be dereferenced.
#### Cross-`basic_json` conversion requirements
### Cross-`basic_json` conversion requirements
When converting a string value from one `basic_json` specialization to another via the
[converting constructor](basic_json.md#overload-4), the target `string_t` must be directly
[converting constructor](basic_json.md) (overload 4), the target `string_t` must be directly
constructible from the source `basic_json`'s `string_t` type. If this requirement is not met, the
conversion does not fail; instead, the string is silently converted as an array of character codes,
which is incorrect. See [issue #3425](https://github.com/nlohmann/json/issues/3425) for details
@@ -80,6 +80,12 @@ and an example.
--8<-- "examples/string_t.output"
```
## See also
- [object_t](object_t.md) the type used to store JSON objects (and their keys, which are also `string_t`)
- [binary_t](binary_t.md) the type used to store binary values
- [get_ptr](get_ptr.md) returns a pointer to the stored string value
## Version history
- Added in version 1.0.0.
+15 -5
View File
@@ -65,6 +65,16 @@ void swap(typename binary_t::container_type& other);
`right` (in, out)
: value to exchange the contents with
## Exception safety
1. No-throw guarantee: this function never throws exceptions.
2. No-throw guarantee: this function never throws exceptions.
3. Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
4. Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
5. Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
6. Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
7. Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
## Exceptions
1. No-throw guarantee: this function never throws exceptions.
@@ -86,7 +96,7 @@ Constant.
## Examples
??? example "Example: Swap JSON value (1, 2)"
??? example "Example: (1, 2) swap JSON values"
The example below shows how JSON values can be swapped with `swap()`.
@@ -100,7 +110,7 @@ Constant.
--8<-- "examples/swap__reference.output"
```
??? example "Example: Swap array (3)"
??? example "Example: (3) swap array"
The example below shows how arrays can be swapped with `swap()`.
@@ -114,7 +124,7 @@ Constant.
--8<-- "examples/swap__array_t.output"
```
??? example "Example: Swap object (4)"
??? example "Example: (4) swap object"
The example below shows how objects can be swapped with `swap()`.
@@ -128,7 +138,7 @@ Constant.
--8<-- "examples/swap__object_t.output"
```
??? example "Example: Swap string (5)"
??? example "Example: (5) swap string"
The example below shows how strings can be swapped with `swap()`.
@@ -142,7 +152,7 @@ Constant.
--8<-- "examples/swap__string_t.output"
```
??? example "Example: Swap binary (6)"
??? example "Example: (6) swap binary"
The example below shows how binary values can be swapped with `swap()`.
+17 -2
View File
@@ -55,7 +55,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
## Exceptions
- Throws [`other_error.502`](../../home/exceptions.md#jsonexceptionother_error502) if `use_type` is true and `use_size`
is false.
is false, and `j` contains a non-empty array, object, or binary value.
## Complexity
@@ -63,7 +63,7 @@ Linear in the size of the JSON value `j`.
## Examples
??? example
??? example "Example: serialize a JSON value to BJData"
The example shows the serialization of a JSON value to a byte vector in BJData format.
@@ -77,6 +77,21 @@ Linear in the size of the JSON value `j`.
--8<-- "examples/to_bjdata.output"
```
??? example "Example: other_error.502 exception"
The example shows how requesting type annotations (`use_type`) without size annotations (`use_size`) throws an
exception, because type-optimized containers can only be read back with a preceding size.
```cpp
--8<-- "examples/to_bjdata__exception.cpp"
```
Output:
```json
--8<-- "examples/to_bjdata__exception.output"
```
## See also
- [from_bjdata](from_bjdata.md) create a JSON value from an input in BJData format
+16 -1
View File
@@ -48,7 +48,7 @@ Linear in the size of the JSON value `j`.
## Examples
??? example
??? example "Example: serialize a JSON value to BON8"
The example shows the serialization of a JSON value to a byte vector in BON8 format.
@@ -62,6 +62,21 @@ Linear in the size of the JSON value `j`.
--8<-- "examples/to_bon8.output"
```
??? example "Example: type_error.316 exception"
The example shows how serializing a string that is not valid UTF-8 throws an exception, because BON8 stores strings
as UTF-8.
```cpp
--8<-- "examples/to_bon8__exception.cpp"
```
Output:
```json
--8<-- "examples/to_bon8__exception.output"
```
## See also
- [from_bon8](from_bon8.md) create a JSON value from an input in BON8 format
+20 -1
View File
@@ -43,6 +43,9 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [`out_of_range.412`](../../home/exceptions.md#jsonexceptionout_of_range412) if the length of a document, array,
string, or binary value exceeds the range of the 32-bit BSON length field; example:
`"BSON length 2147483661 exceeds maximum of 2147483647"`
- Throws [`out_of_range.415`](../../home/exceptions.md#jsonexceptionout_of_range415) if the subtype of a binary value
exceeds 255, the maximum of the BSON binary subtype; example:
`"subtype 300 is too large for the BSON binary subtype (max 255)"`
## Complexity
@@ -51,7 +54,7 @@ pass before anything is written.
## Examples
??? example
??? example "Example: serialize a JSON value to BSON"
The example shows the serialization of a JSON value to a byte vector in BSON format.
@@ -65,6 +68,21 @@ pass before anything is written.
--8<-- "examples/to_bson.output"
```
??? example "Example: out_of_range.409 exception"
The example shows how serializing a JSON object whose key contains a null byte (U+0000) throws an exception, because
BSON keys are null-terminated C strings and cannot contain U+0000 themselves.
```cpp
--8<-- "examples/to_bson__exception.cpp"
```
Output:
```json
--8<-- "examples/to_bson__exception.output"
```
## See also
- [from_bson](from_bson.md) create a JSON value from an input in BSON format
@@ -77,4 +95,5 @@ pass before anything is written.
## Version history
- Added in version 3.4.0.
- Throws `out_of_range.412` and `out_of_range.415` since version 3.13.0.
- Linear in the size of `j`, and no longer limited by the call stack for deeply nested values, since version 3.13.0.
+16 -1
View File
@@ -49,7 +49,7 @@ Linear in the size of the JSON value `j`.
## Examples
??? example
??? example "Example: serialize a JSON value to MessagePack"
The example shows the serialization of a JSON value to a byte vector in MessagePack format.
@@ -63,6 +63,21 @@ Linear in the size of the JSON value `j`.
--8<-- "examples/to_msgpack.output"
```
??? example "Example: out_of_range.415 exception"
The example shows how serializing a binary value whose subtype exceeds 255 throws an exception, because the
MessagePack ext type stores the subtype in a single byte.
```cpp
--8<-- "examples/to_msgpack__exception.cpp"
```
Output:
```json
--8<-- "examples/to_msgpack__exception.output"
```
## See also
- [from_msgpack](from_msgpack.md) create a JSON value from an input in MessagePack format
+2 -1
View File
@@ -10,7 +10,8 @@ This function implements a user-defined to_string for JSON objects.
## Template parameters
`BasicJsonType`
: a specialization of [`basic_json`](index.md)
: a specialization of [`basic_json`](index.md) whose [`string_t`](string_t.md) is convertible to `#!cpp std::string`;
for other string types, use [`dump`](dump.md), which returns a `string_t`
## Return value
+17 -2
View File
@@ -48,7 +48,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
## Exceptions
- Throws [`other_error.502`](../../home/exceptions.md#jsonexceptionother_error502) if `use_type` is true and `use_size`
is false.
is false, and `j` contains a non-empty array, object, or binary value.
## Complexity
@@ -56,7 +56,7 @@ Linear in the size of the JSON value `j`.
## Examples
??? example
??? example "Example: serialize a JSON value to UBJSON"
The example shows the serialization of a JSON value to a byte vector in UBJSON format.
@@ -70,6 +70,21 @@ Linear in the size of the JSON value `j`.
--8<-- "examples/to_ubjson.output"
```
??? example "Example: other_error.502 exception"
The example shows how requesting type annotations (`use_type`) without size annotations (`use_size`) throws an
exception, because type-optimized containers can only be read back with a preceding size.
```cpp
--8<-- "examples/to_ubjson__exception.cpp"
```
Output:
```json
--8<-- "examples/to_ubjson__exception.output"
```
## See also
- [from_ubjson](from_ubjson.md) create a JSON value from an input in UBJSON format
+6
View File
@@ -47,6 +47,12 @@ Constant.
--8<-- "examples/type.output"
```
## See also
- [operator value_t](operator_value_t.md) implicit conversion operator equivalent to this named member function
- [type_name](type_name.md) returns the type as a string, for use in error messages
- [value_t](value_t.md) the enumeration of JSON types
## Version history
- Added in version 1.0.0.
@@ -52,6 +52,11 @@ Constant.
--8<-- "examples/type_name.output"
```
## See also
- [type](type.md) returns the type of the JSON value
- [value_t](value_t.md) the enumeration of JSON types
## Version history
- Added in version 1.0.0.
@@ -27,8 +27,17 @@ The function can throw the following exceptions:
- Throws [`type_error.315`](../../home/exceptions.md#jsonexceptiontype_error315) if object values are not primitive
- Throws [`type_error.313`](../../home/exceptions.md#jsonexceptiontype_error313) if a key (JSON pointer) leads to a
conflicting nesting; example: `"invalid value to unflatten"`
- Throws [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) if an array index in a key begins
with '0'; example: `"array index '01' must not begin with '0'"`
- Throws [`parse_error.107`](../../home/exceptions.md#jsonexceptionparse_error107) if a key is not empty and does not
begin with a slash (`/`); example: `"JSON pointer must be empty or begin with '/' - was: 'a'"`
- Throws [`parse_error.108`](../../home/exceptions.md#jsonexceptionparse_error108) if a tilde (`~`) in a key is not
followed by `0` or `1`; example: `"escape character '~' must be followed with '0' or '1'"`
- Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) if an array index in a key is not a
number; example: `"array index 'one' is not a number"`
- Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if a level becomes an array
(because one of its keys is `0`) and another key at that level cannot be an array index; example:
`"unresolved reference token 'x'"`
## Complexity
+3 -3
View File
@@ -61,7 +61,7 @@ Basic guarantee: if an exception is thrown during the operation, the JSON value
## Examples
??? example
??? example "Example: (1) update with another object"
The example shows how `update()` is used.
@@ -75,7 +75,7 @@ Basic guarantee: if an exception is thrown during the operation, the JSON value
--8<-- "examples/update.output"
```
??? example
??? example "Example: (2) update with an iterator range"
The example shows how `update()` is used.
@@ -89,7 +89,7 @@ Basic guarantee: if an exception is thrown during the operation, the JSON value
--8<-- "examples/update__range.output"
```
??? example
??? example "Example: (1) merge user settings into default settings"
One common use case for this function is the handling of user settings. Assume your application can be configured in
some aspects:
+27
View File
@@ -133,6 +133,18 @@ changes to any JSON value.
--8<-- "examples/value__return_type.output"
```
!!! warning "Deprecation"
Overload (3) also accepts a [`json_pointer`](../json_pointer/index.md) whose template argument is a `basic_json`
specialization (e.g., `nlohmann::json_pointer<nlohmann::json>`) instead of a string type. This is deprecated since
version 3.11.0 and will be removed in a future major version; use `basic_json::json_pointer` (for `json`,
`nlohmann::json_pointer<std::string>`) instead.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
See the [migration guide](../../integration/migration_guide.md#json-pointers) for how to update existing code.
## Examples
??? example "Example: (1) access specified object element with default value"
@@ -177,6 +189,21 @@ changes to any JSON value.
--8<-- "examples/value__json_ptr.output"
```
??? example "Example: (1) type_error.302 and type_error.306 exceptions"
The example below shows how `value()` throws `type_error.302` when the default value's type does not match the type
of the stored value, and `type_error.306` when `value()` is called on a JSON value that is not an object.
```cpp
--8<-- "examples/value__exception.cpp"
```
Output:
```json
--8<-- "examples/value__exception.output"
```
## See also
- see [`at`](at.md) for access by reference with range checking
@@ -38,6 +38,16 @@ functions [`is_null`](is_null.md), [`is_object`](is_object.md), [`is_array`](is_
`discarded` is unordered.
```mermaid
flowchart LR
A[null] --> B[boolean]
B --> C["number_integer / number_unsigned / number_float"]
C --> D[object]
D --> E[array]
E --> F[string]
F --> G[binary]
```
!!! note "Types of numbers"
There are three enumerators for numbers (`number_integer`, `number_unsigned`, and `number_float`) to distinguish
@@ -74,6 +84,14 @@ functions [`is_null`](is_null.md), [`is_object`](is_object.md), [`is_array`](is_
--8<-- "examples/type.output"
```
## See also
- [type](type.md) return the type of the JSON value
- [type_name](type_name.md) return the type as string
- [operator value_t](operator_value_t.md) return the type of the JSON value
- [is_primitive](is_primitive.md) return whether the type is primitive
- [is_structured](is_structured.md) return whether the type is structured
## Version history
- Added in version 1.0.0.
@@ -16,6 +16,11 @@ Linear.
<!-- NOLINT Examples -->
## See also
- [basic_json](basic_json.md) constructs a JSON value
- [clear](clear.md) clears the content of a JSON value without destroying it
## Version history
- Added in version 1.0.0.
@@ -41,6 +41,14 @@ byte_container_with_subtype(container_type&& container, subtype_type subtype);
--8<-- "examples/byte_container_with_subtype__byte_container_with_subtype.output"
```
## See also
- [set_subtype](set_subtype.md) sets the binary subtype
- [subtype](subtype.md) return the binary subtype
- [has_subtype](has_subtype.md) return whether the value has a subtype
- [binary](../basic_json/binary.md) create a binary JSON value
- [Binary Values](../../features/binary_values.md) - the article on binary values
## Version history
Since version 3.8.0.
@@ -31,6 +31,12 @@ Constant.
--8<-- "examples/byte_container_with_subtype__clear_subtype.output"
```
## See also
- [set_subtype](set_subtype.md) sets the binary subtype
- [has_subtype](has_subtype.md) return whether the value has a subtype
- [subtype](subtype.md) return the binary subtype
## Version history
Since version 3.8.0.
@@ -34,6 +34,12 @@ Constant.
--8<-- "examples/byte_container_with_subtype__has_subtype.output"
```
## See also
- [set_subtype](set_subtype.md) sets the binary subtype
- [clear_subtype](clear_subtype.md) clears the binary subtype
- [subtype](subtype.md) return the binary subtype
## Version history
Since version 3.8.0.
@@ -22,8 +22,8 @@ specific naming scheme in order to override the binary type.
## Member functions
- [(constructor)](byte_container_with_subtype.md)
- **operator==** - comparison: equal
- **operator!=** - comparison: not equal
- [**operator==**](operator_eq.md) - comparison: equal
- [**operator!=**](operator_ne.md) - comparison: not equal
- [**set_subtype**](set_subtype.md) - sets the binary subtype
- [**subtype**](subtype.md) - return the binary subtype
- [**has_subtype**](has_subtype.md) - return whether the value has a subtype
@@ -0,0 +1,48 @@
# <small>nlohmann::byte_container_with_subtype::</small>operator==
```cpp
bool operator==(const byte_container_with_subtype& rhs) const;
```
Compares two byte containers for equality by comparing (1) the underlying binary data (the `BinaryType` base, compared
with `BinaryType`'s own `operator==`) and (2) the subtype information -- both containers must either have no subtype,
or have a subtype and the same subtype value.
## Parameters
`rhs` (in)
: byte container to compare `*this` with
## Return value
whether `*this` and `rhs` are equal
## Complexity
Linear in the size of the compared containers.
## Examples
??? example
The example below demonstrates comparing byte containers with and without subtypes.
```cpp
--8<-- "examples/byte_container_with_subtype__operator__equal.cpp"
```
Output:
```json
--8<-- "examples/byte_container_with_subtype__operator__equal.output"
```
## See also
- [operator!=](operator_ne.md) comparison: not equal
- [has_subtype](has_subtype.md) return whether the value has a subtype
- [subtype](subtype.md) return the binary subtype
## Version history
- Added in version 3.8.0.
@@ -0,0 +1,47 @@
# <small>nlohmann::byte_container_with_subtype::</small>operator!=
```cpp
bool operator!=(const byte_container_with_subtype& rhs) const;
```
Compares two byte containers for inequality. Returns `#!cpp !(rhs == *this)`; see [`operator==`](operator_eq.md) for
the equality semantics.
## Parameters
`rhs` (in)
: byte container to compare `*this` with
## Return value
whether `*this` and `rhs` are not equal
## Complexity
Linear in the size of the compared containers.
## Examples
??? example
The example below demonstrates comparing byte containers with and without subtypes.
```cpp
--8<-- "examples/byte_container_with_subtype__operator__notequal.cpp"
```
Output:
```json
--8<-- "examples/byte_container_with_subtype__operator__notequal.output"
```
## See also
- [operator==](operator_eq.md) comparison: equal
- [has_subtype](has_subtype.md) return whether the value has a subtype
- [subtype](subtype.md) return the binary subtype
## Version history
- Added in version 3.8.0.
@@ -36,6 +36,12 @@ Constant.
--8<-- "examples/byte_container_with_subtype__set_subtype.output"
```
## See also
- [subtype](subtype.md) return the binary subtype
- [has_subtype](has_subtype.md) return whether the value has a subtype
- [clear_subtype](clear_subtype.md) clears the binary subtype
## Version history
Since version 3.8.0.

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