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