forked from Research/WhisperCom
61 lines
1.5 KiB
Markdown
61 lines
1.5 KiB
Markdown
|
# basic_json::get_ptr
|
||
|
|
|
||
|
|
```cpp
|
||
|
|
template<typename PointerType>
|
||
|
|
PointerType get_ptr();
|
||
|
|
|
||
|
|
template<typename PointerType>
|
||
|
|
constexpr const PointerType get_ptr() const noexcept;
|
||
|
|
```
|
||
|
|
|
||
|
|
Implicit pointer access to the internally stored JSON value. No copies are made.
|
||
|
|
|
||
|
|
## Template arguments
|
||
|
|
|
||
|
|
`PointerType`
|
||
|
|
: pointer type; must be a pointer to [`array_t`](array_t.md), [`object_t`](object_t.md), [`string_t`](string_t.md),
|
||
|
|
[`boolean_t`](boolean_t.md), [`number_integer_t`](number_integer_t.md), or
|
||
|
|
[`number_unsigned_t`](number_unsigned_t.md), [`number_float_t`](number_float_t.md), or [`binary_t`](binary_t.md).
|
||
|
|
Other types will not compile.
|
||
|
|
|
||
|
|
## Return value
|
||
|
|
|
||
|
|
pointer to the internally stored JSON value if the requested pointer type fits to the JSON value; `#!cpp nullptr`
|
||
|
|
otherwise
|
||
|
|
|
||
|
|
## Exception safety
|
||
|
|
|
||
|
|
Strong exception safety: if an exception occurs, the original value stays intact.
|
||
|
|
|
||
|
|
## Complexity
|
||
|
|
|
||
|
|
Constant.
|
||
|
|
|
||
|
|
## Notes
|
||
|
|
|
||
|
|
!!! warning
|
||
|
|
|
||
|
|
Writing data to the pointee of the result yields an undefined state.
|
||
|
|
|
||
|
|
## Example
|
||
|
|
|
||
|
|
??? example
|
||
|
|
|
||
|
|
The example below shows how pointers to internal values of a JSON value can be requested. Note that no type
|
||
|
|
conversions are made and a `#!cpp nullptr` is returned if the value and the requested pointer type does not match.
|
||
|
|
|
||
|
|
```cpp
|
||
|
|
--8<-- "examples/get_ptr.cpp"
|
||
|
|
```
|
||
|
|
|
||
|
|
Output:
|
||
|
|
|
||
|
|
```json
|
||
|
|
--8<-- "examples/get_ptr.output"
|
||
|
|
```
|
||
|
|
|
||
|
|
## Version history
|
||
|
|
|
||
|
|
- Added in version 1.0.0.
|
||
|
|
- Extended to binary types in version 3.8.0.
|