[ceph.git] / ceph / src / jaegertracing / opentelemetry-cpp / third_party / nlohmann-json / doc / mkdocs / docs / api / basic_json / meta.md

# <small>nlohmann::basic_json::</small>meta

```cpp
static basic_json meta();
```

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). |
| `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](http://semver.org), 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.
    
    ```cpp
    --8<-- "examples/meta.cpp"
    ```
    
    Output:
    
    ```json
    --8<-- "examples/meta.output"
    ```

## Version history

- Added in version 2.1.0.
Commit	Line	Data
1e59de90 TL	1	# <small>nlohmann::basic_json::</small>meta
	2
	3	```cpp
	4	static basic_json meta();
	5	```
	6
	7	This function returns a JSON object with information about the library, including the version number and information on
	8	the platform and compiler.
	9
	10	## Return value
	11
	12	JSON object holding version information
	13
	14	\| key \| description \|
	15	\|-------------\|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------\|
	16	\| `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). \|
	17	\| `copyright` \| The copyright line for the library as string. \|
	18	\| `name` \| The name of the library as string. \|
	19	\| `platform` \| The used platform as string. Possible values are `win32`, `linux`, `apple`, `unix`, and `unknown`. \|
	20	\| `url` \| The URL of the project as string. \|
	21	\| `version` \| The version of the library. It is an object with the following keys: `major`, `minor`, and `patch` as defined by [Semantic Versioning](http://semver.org), and `string` (the version string). \|
	22
	23	## Exception safety
	24
	25	Strong guarantee: if an exception is thrown, there are no changes to any JSON value.
	26
	27	## Complexity
	28
	29	Constant.
	30
	31	## Examples
	32
	33	??? example
	34
	35	The following code shows an example output of the `meta()`
	36	function.
	37
	38	```cpp
	39	--8<-- "examples/meta.cpp"
	40	```
	41
	42	Output:
	43
	44	```json
	45	--8<-- "examples/meta.output"
	46	```
	47
	48	## Version history
	49
	50	- Added in version 2.1.0.