json/doc/mkdocs/docs/api/basic_json/is_boolean.md

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2020-08-12 19:41:59 +08:00
# basic_json::is_boolean
```cpp
constexpr bool is_boolean() const noexcept;
```
This function returns `#!cpp true` if and only if the JSON value is `#!json true` or `#!json false`.
## Return value
`#!cpp true` if type is boolean, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this member function never throws exceptions.
## Complexity
Constant.
## Example
??? example
The following code exemplifies `is_boolean()` for all JSON types.
```cpp
--8<-- "examples/is_boolean.cpp"
```
Output:
```json
--8<-- "examples/is_boolean.output"
```
## Version history
- Added in version 1.0.0.