nlohmann::basic_json::meta¶
staticbasic_jsonmeta();
This function returns a JSON object with information about the library, including the version number and information on the platform and compiler.
Return value¶
JSON object holding version information
| key | description |
|---|---|
compiler | Information on the used compiler. It is an object with the following keys: c++ (the used C++ standard), family (the compiler family; possible values are clang, icc, gcc, ilecpp, msvc, pgcpp, sunpro, and unknown), and version (the compiler version). On HP aCC compilers, compiler is instead the plain string hp. |
copyright | The copyright line for the library as string. |
name | The name of the library as string. |
platform | The used platform as string. Possible values are win32, linux, apple, unix, and unknown. |
url | The URL of the project as string. |
version | The version of the library. It is an object with the following keys: major, minor, and patch as defined by Semantic Versioning, and string (the version string). |
Exception safety¶
Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
Complexity¶
Constant.
Examples¶
Example
The following code shows an example output of the meta() function.
#include<iostream>
#include<iomanip>
#include<nlohmann/json.hpp>
usingjson=nlohmann::json;
intmain()
{
// call meta()
std::cout<<std::setw(4)<<json::meta()<<'\n';
}
Output:
{
"compiler":{
"c++":"201103",
"family":"gcc",
"version":"12.4.0"
},
"copyright":"(C) 2013-2026 Niels Lohmann",
"name":"JSON for Modern C++",
"platform":"apple",
"url":"https://github.com/nlohmann/json",
"version":{
"major":3,
"minor":12,
"patch":0,
"string":"3.12.0"
}
}
Note the output is platform-dependent.
See also¶
- NLOHMANN_JSON_VERSION_MAJOR/NLOHMANN_JSON_VERSION_MINOR/NLOHMANN_JSON_VERSION_PATCH - library version information
Version history¶
- Added in version 2.1.0.