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@@ -72,27 +72,11 @@
|
||||
<span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>contains</span><span class=p>(</span><span class=s>"/array/1"</span><span class=n>_json_pointer</span><span class=p>)</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=sc>'\n'</span>
|
||||
<span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>contains</span><span class=p>(</span><span class=s>"/array/-"</span><span class=n>_json_pointer</span><span class=p>)</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=sc>'\n'</span>
|
||||
<span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>contains</span><span class=p>(</span><span class=s>"/array/4"</span><span class=n>_json_pointer</span><span class=p>)</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=sc>'\n'</span>
|
||||
<span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>contains</span><span class=p>(</span><span class=s>"/baz"</span><span class=n>_json_pointer</span><span class=p>)</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
|
||||
|
||||
<span class=w> </span><span class=k>try</span>
|
||||
<span class=w> </span><span class=p>{</span>
|
||||
<span class=w> </span><span class=c1>// try to use an array index with leading '0'</span>
|
||||
<span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>contains</span><span class=p>(</span><span class=s>"/array/01"</span><span class=n>_json_pointer</span><span class=p>);</span>
|
||||
<span class=w> </span><span class=p>}</span>
|
||||
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse_error</span><span class=o>&</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
|
||||
<span class=w> </span><span class=p>{</span>
|
||||
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
|
||||
<span class=w> </span><span class=p>}</span>
|
||||
|
||||
<span class=w> </span><span class=k>try</span>
|
||||
<span class=w> </span><span class=p>{</span>
|
||||
<span class=w> </span><span class=c1>// try to use an array index that is not a number</span>
|
||||
<span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>contains</span><span class=p>(</span><span class=s>"/array/one"</span><span class=n>_json_pointer</span><span class=p>);</span>
|
||||
<span class=w> </span><span class=p>}</span>
|
||||
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse_error</span><span class=o>&</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
|
||||
<span class=w> </span><span class=p>{</span>
|
||||
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
|
||||
<span class=w> </span><span class=p>}</span>
|
||||
<span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>contains</span><span class=p>(</span><span class=s>"/baz"</span><span class=n>_json_pointer</span><span class=p>)</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=sc>'\n'</span>
|
||||
<span class=w> </span><span class=c1>// an array index with a leading '0' is not found</span>
|
||||
<span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>contains</span><span class=p>(</span><span class=s>"/array/01"</span><span class=n>_json_pointer</span><span class=p>)</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=sc>'\n'</span>
|
||||
<span class=w> </span><span class=c1>// an array index that is not a number is not found</span>
|
||||
<span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>contains</span><span class=p>(</span><span class=s>"/array/one"</span><span class=n>_json_pointer</span><span class=p>)</span><span class=w> </span><span class=o><<</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
|
||||
<span class=p>}</span>
|
||||
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=kc>true</span>
|
||||
<span class=kc>true</span>
|
||||
@@ -101,4 +85,6 @@
|
||||
<span class=kc>false</span>
|
||||
<span class=kc>false</span>
|
||||
<span class=kc>false</span>
|
||||
<span class=kc>false</span>
|
||||
<span class=kc>false</span>
|
||||
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">¶</a></h2> <ul> <li><a href=../find/ >find</a> find a value in an object</li> <li><a href=../count/ >count</a> returns the number of occurrences of a key</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">¶</a></h2> <ol> <li>Added in version 3.11.0.</li> <li>Added in version 3.6.0. Extended template <code>KeyType</code> to support comparable types in version 3.11.0. Fixed in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span> to consistently accept <code>std::string_view</code>-convertible keys, as already supported by <a href=../operator%5B%5D/ ><code>operator[]</code></a>, <a href=../at/ ><code>at</code></a>, <a href=../value/ ><code>value</code></a>, and other lookup functions.</li> <li>Added in version 3.7.0.</li> <li>Deleted overloads for integral key types added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span> to reject such calls at compile time instead of causing undefined behavior at runtime.</li> </ol> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="October 4, 2026 09:46:32 UTC">October 4, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright © 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </a> <a href="https://www.linkedin.com/in/nielslohmann/" target="_blank" rel="noopener" title="www.linkedin.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 448 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontaLine truncated
|
||||
@@ -160,27 +160,11 @@ int main()
|
||||
<< j.contains("/array/1"_json_pointer) << '\n'
|
||||
<< j.contains("/array/-"_json_pointer) << '\n'
|
||||
<< j.contains("/array/4"_json_pointer) << '\n'
|
||||
<< j.contains("/baz"_json_pointer) << std::endl;
|
||||
|
||||
try
|
||||
{
|
||||
// try to use an array index with leading '0'
|
||||
j.contains("/array/01"_json_pointer);
|
||||
}
|
||||
catch (const json::parse_error& e)
|
||||
{
|
||||
std::cout << e.what() << '\n';
|
||||
}
|
||||
|
||||
try
|
||||
{
|
||||
// try to use an array index that is not a number
|
||||
j.contains("/array/one"_json_pointer);
|
||||
}
|
||||
catch (const json::parse_error& e)
|
||||
{
|
||||
std::cout << e.what() << '\n';
|
||||
}
|
||||
<< j.contains("/baz"_json_pointer) << '\n'
|
||||
// an array index with a leading '0' is not found
|
||||
<< j.contains("/array/01"_json_pointer) << '\n'
|
||||
// an array index that is not a number is not found
|
||||
<< j.contains("/array/one"_json_pointer) << std::endl;
|
||||
}
|
||||
```
|
||||
|
||||
@@ -194,6 +178,8 @@ true
|
||||
false
|
||||
false
|
||||
false
|
||||
false
|
||||
false
|
||||
```
|
||||
|
||||
## See also
|
||||
|
||||
@@ -37,7 +37,7 @@
|
||||
<span class=w> </span><span class=k>try</span>
|
||||
<span class=w> </span><span class=p>{</span>
|
||||
<span class=w> </span><span class=c1>// parsing input with a syntax error</span>
|
||||
<span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse</span><span class=p>(</span><span class=s>"[1,2,3,]"</span><span class=p>);</span>
|
||||
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse</span><span class=p>(</span><span class=s>"[1,2,3,]"</span><span class=p>);</span>
|
||||
<span class=w> </span><span class=p>}</span>
|
||||
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse_error</span><span class=o>&</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
|
||||
<span class=w> </span><span class=p>{</span>
|
||||
|
||||
@@ -72,7 +72,7 @@ int main()
|
||||
try
|
||||
{
|
||||
// parsing input with a syntax error
|
||||
json::parse("[1,2,3,]");
|
||||
json j = json::parse("[1,2,3,]");
|
||||
}
|
||||
catch (const json::parse_error& e)
|
||||
{
|
||||
|
||||
@@ -19,25 +19,9 @@ int main()
|
||||
<< j.contains("/array/1"_json_pointer) << '\n'
|
||||
<< j.contains("/array/-"_json_pointer) << '\n'
|
||||
<< j.contains("/array/4"_json_pointer) << '\n'
|
||||
<< j.contains("/baz"_json_pointer) << std::endl;
|
||||
|
||||
try
|
||||
{
|
||||
// try to use an array index with leading '0'
|
||||
j.contains("/array/01"_json_pointer);
|
||||
}
|
||||
catch (const json::parse_error& e)
|
||||
{
|
||||
std::cout << e.what() << '\n';
|
||||
}
|
||||
|
||||
try
|
||||
{
|
||||
// try to use an array index that is not a number
|
||||
j.contains("/array/one"_json_pointer);
|
||||
}
|
||||
catch (const json::parse_error& e)
|
||||
{
|
||||
std::cout << e.what() << '\n';
|
||||
}
|
||||
<< j.contains("/baz"_json_pointer) << '\n'
|
||||
// an array index with a leading '0' is not found
|
||||
<< j.contains("/array/01"_json_pointer) << '\n'
|
||||
// an array index that is not a number is not found
|
||||
<< j.contains("/array/one"_json_pointer) << std::endl;
|
||||
}
|
||||
@@ -5,3 +5,5 @@ true
|
||||
false
|
||||
false
|
||||
false
|
||||
false
|
||||
false
|
||||
@@ -8,7 +8,7 @@ int main()
|
||||
try
|
||||
{
|
||||
// parsing input with a syntax error
|
||||
json::parse("[1,2,3,]");
|
||||
json j = json::parse("[1,2,3,]");
|
||||
}
|
||||
catch (const json::parse_error& e)
|
||||
{
|
||||
|
||||
@@ -88,7 +88,7 @@
|
||||
<span class=w> </span><span class=k>try</span>
|
||||
<span class=w> </span><span class=p>{</span>
|
||||
<span class=w> </span><span class=c1>// parsing input with a syntax error</span>
|
||||
<span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse</span><span class=p>(</span><span class=s>"[1,2,3,]"</span><span class=p>);</span>
|
||||
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse</span><span class=p>(</span><span class=s>"[1,2,3,]"</span><span class=p>);</span>
|
||||
<span class=w> </span><span class=p>}</span>
|
||||
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse_error</span><span class=o>&</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
|
||||
<span class=w> </span><span class=p>{</span>
|
||||
|
||||
@@ -168,7 +168,7 @@ int main()
|
||||
try
|
||||
{
|
||||
// parsing input with a syntax error
|
||||
json::parse("[1,2,3,]");
|
||||
json j = json::parse("[1,2,3,]");
|
||||
}
|
||||
catch (const json::parse_error& e)
|
||||
{
|
||||
|
||||
@@ -1 +1 @@
|
||||
{"config":{"lang":["en"],"separator":"[\\s\\-\\.]","pipeline":["stopWordFilter"],"fields":{"title":{"boost":1000.0},"text":{"boost":1.0},"tags":{"boost":1000000.0}}},"docs":[{"location":"","title":"JSON for Modern C++","text":"<p>JSON for Modern C++ is a header-only C++11 library that turns JSON into a first-class C++ data type, using the operator magic of modern C++ so that creating, reading, and modifying JSON values feels as natural as it does in languages like Python. The whole library is available as a single header, <code>json.hpp</code>, with no dependencies, no subproject, and no complex build system to set up; a companion header, <code>json_fwd.hpp</code>, provides forward declarations to keep compile times down. See header-only integration for details. It is heavily unit-tested with 100% code coverage, checked with Valgrind and the Clang Sanitizers for memory leaks, and continuously fuzz-tested by Google OSS-Fuzz.</p>"},{"location":"#quick-start","title":"Quick start","text":"<p>Add the single header to your project and use the library like this:</p> <pre><code>#include <iostream>\n#include <nlohmann/json.hpp>\n\nusing json = nlohmann::json;\n\nint main()\n{\n // parse a JSON string\n json j = json::parse(R\"({\"happy\": true, \"pi\": 3.141})\");\n\n // access and modify values\n j[\"name\"] = \"Niels\";\n j[\"list\"] = {1, 0, 2};\n\n // serialize with an indent of 4 spaces\n std::cout << j.dump(4) << '\\n';\n}\n</code></pre> <p>Get the library by copying the single header <code>json.hpp</code> from the releases page into a directory <code>nlohmann</code> on your include path, or by installing it with a package manager:</p> <pre><code>brew install nlohmann-json # Homebrew\nvcpkg install nlohmann-json # vcpkg\n</code></pre> <pre><code>find_package(nlohmann_json 3.12.0 REQUIRED)\ntarget_link_libraries(myproject PRIVATE nlohmann_json::nlohmann_json)\n</code></pre> <p>See Integration for CMake in detail, all supported package managers (Conan, Meson, Bazel, Conda, and more), and pkg-config.</p>"},{"location":"#explore-the-documentation","title":"Explore the documentation","text":"<ul> <li> <p> Features</p> <p>Creating, parsing, accessing, and serializing JSON values, JSON Pointer/Patch, binary formats, and more.</p> <p> Features</p> </li> <li> <p> Integration</p> <p>Add the library to your project via a single header, CMake, a package manager, or pkg-config.</p> <p> Integration</p> </li> <li> <p> API documentation</p> <p>The complete reference for <code>basic_json</code> and its member functions, types, and related classes.</p> <p> API documentation</p> </li> <li> <p> FAQ</p> <p>Answers to common questions and known surprises when using the library.</p> <p> FAQ</p> </li> <li> <p> Releases</p> <p>What changed in each release, with links to the relevant documentation.</p> <p> Releases</p> </li> <li> <p> Community</p> <p>The ecosystem, contribution guidelines, governance, and quality assurance around the project.</p> <p> Community</p> </li> </ul> <p>Unreleased changes</p> <p>This documentation is built from the <code>develop</code> branch and may describe changes that are not part of a release yet. Their version numbers are followed by an unreleased badge; see Releases for what shipped in each version.</p> <p>The library is licensed under the MIT License. The source code, issue tracker, and discussions are on GitHub.</p>"},{"location":"api/json/","title":"nlohmann::json","text":"<pre><code>using json = basic_json<>;\n</code></pre> <p>This type is the default specialization of the basic_json class which uses the standard template types.</p>"},{"location":"api/json/#examples","title":"Examples","text":"Example <p>The example below demonstrates how to use the type <code>nlohmann::json</code>.</p> <pre><code>#include <iostream>\n#include <iomanip>\n#include <nlohmann/json.hpp>\n\nusing json = nlohmann::json;\n\nint main()\n{\n // create a JSON object\n json j =\n {\n {\"pi\", 3.141},\n {\"happy\", true},\n {\"name\", \"Niels\"},\n {\"nothing\", nullptr},\n {\n \"answer\", {\n {\"everything\", 42}\n }\n },\n {\"list\", {1, 0, 2}},\n {\n \"object\", {\n {\"currency\", \"USD\"},\n {\"value\", 42.99}\n }\n }\n };\n\n // add new values\n j[\"new\"][\"key\"][\"value\"] = {\"another\", \"list\"};\n\n // count elements\n auto s = j.size();\n j[\"size\"] = s;\n\n // pretty print with indent of 4 spaces\n std::cout << std::setw(4) << j << '\\n';\n}\n</code></pre> <p>Output:</p> <pre><code>{\n \"answer\": {\n \"everything\": 42\n },\n \"happy\": true,\n \"list\": [\n 1,\n 0,\n 2\n ],\n \"name\": \"Niels\",\n \"new\": {\n \"key\": {\n \"value\": [\n \"another\",\n Line truncated
|
||||
{"config":{"lang":["en"],"separator":"[\\s\\-\\.]","pipeline":["stopWordFilter"],"fields":{"title":{"boost":1000.0},"text":{"boost":1.0},"tags":{"boost":1000000.0}}},"docs":[{"location":"","title":"JSON for Modern C++","text":"<p>JSON for Modern C++ is a header-only C++11 library that turns JSON into a first-class C++ data type, using the operator magic of modern C++ so that creating, reading, and modifying JSON values feels as natural as it does in languages like Python. The whole library is available as a single header, <code>json.hpp</code>, with no dependencies, no subproject, and no complex build system to set up; a companion header, <code>json_fwd.hpp</code>, provides forward declarations to keep compile times down. See header-only integration for details. It is heavily unit-tested with 100% code coverage, checked with Valgrind and the Clang Sanitizers for memory leaks, and continuously fuzz-tested by Google OSS-Fuzz.</p>"},{"location":"#quick-start","title":"Quick start","text":"<p>Add the single header to your project and use the library like this:</p> <pre><code>#include <iostream>\n#include <nlohmann/json.hpp>\n\nusing json = nlohmann::json;\n\nint main()\n{\n // parse a JSON string\n json j = json::parse(R\"({\"happy\": true, \"pi\": 3.141})\");\n\n // access and modify values\n j[\"name\"] = \"Niels\";\n j[\"list\"] = {1, 0, 2};\n\n // serialize with an indent of 4 spaces\n std::cout << j.dump(4) << '\\n';\n}\n</code></pre> <p>Get the library by copying the single header <code>json.hpp</code> from the releases page into a directory <code>nlohmann</code> on your include path, or by installing it with a package manager:</p> <pre><code>brew install nlohmann-json # Homebrew\nvcpkg install nlohmann-json # vcpkg\n</code></pre> <pre><code>find_package(nlohmann_json 3.12.0 REQUIRED)\ntarget_link_libraries(myproject PRIVATE nlohmann_json::nlohmann_json)\n</code></pre> <p>See Integration for CMake in detail, all supported package managers (Conan, Meson, Bazel, Conda, and more), and pkg-config.</p>"},{"location":"#explore-the-documentation","title":"Explore the documentation","text":"<ul> <li> <p> Features</p> <p>Creating, parsing, accessing, and serializing JSON values, JSON Pointer/Patch, binary formats, and more.</p> <p> Features</p> </li> <li> <p> Integration</p> <p>Add the library to your project via a single header, CMake, a package manager, or pkg-config.</p> <p> Integration</p> </li> <li> <p> API documentation</p> <p>The complete reference for <code>basic_json</code> and its member functions, types, and related classes.</p> <p> API documentation</p> </li> <li> <p> FAQ</p> <p>Answers to common questions and known surprises when using the library.</p> <p> FAQ</p> </li> <li> <p> Releases</p> <p>What changed in each release, with links to the relevant documentation.</p> <p> Releases</p> </li> <li> <p> Community</p> <p>The ecosystem, contribution guidelines, governance, and quality assurance around the project.</p> <p> Community</p> </li> </ul> <p>Unreleased changes</p> <p>This documentation is built from the <code>develop</code> branch and may describe changes that are not part of a release yet. Their version numbers are followed by an unreleased badge; see Releases for what shipped in each version.</p> <p>The library is licensed under the MIT License. The source code, issue tracker, and discussions are on GitHub.</p>"},{"location":"api/json/","title":"nlohmann::json","text":"<pre><code>using json = basic_json<>;\n</code></pre> <p>This type is the default specialization of the basic_json class which uses the standard template types.</p>"},{"location":"api/json/#examples","title":"Examples","text":"Example <p>The example below demonstrates how to use the type <code>nlohmann::json</code>.</p> <pre><code>#include <iostream>\n#include <iomanip>\n#include <nlohmann/json.hpp>\n\nusing json = nlohmann::json;\n\nint main()\n{\n // create a JSON object\n json j =\n {\n {\"pi\", 3.141},\n {\"happy\", true},\n {\"name\", \"Niels\"},\n {\"nothing\", nullptr},\n {\n \"answer\", {\n {\"everything\", 42}\n }\n },\n {\"list\", {1, 0, 2}},\n {\n \"object\", {\n {\"currency\", \"USD\"},\n {\"value\", 42.99}\n }\n }\n };\n\n // add new values\n j[\"new\"][\"key\"][\"value\"] = {\"another\", \"list\"};\n\n // count elements\n auto s = j.size();\n j[\"size\"] = s;\n\n // pretty print with indent of 4 spaces\n std::cout << std::setw(4) << j << '\\n';\n}\n</code></pre> <p>Output:</p> <pre><code>{\n \"answer\": {\n \"everything\": 42\n },\n \"happy\": true,\n \"list\": [\n 1,\n 0,\n 2\n ],\n \"name\": \"Niels\",\n \"new\": {\n \"key\": {\n \"value\": [\n \"another\",\n Line truncated
|
||||
Reference in new issue
Block a user