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636 B
636 B
basic_json::is_null
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.