• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1# <small>nlohmann::basic_json::</small>get_ptr
2
3```cpp
4template<typename PointerType>
5PointerType get_ptr() noexcept;
6
7template<typename PointerType>
8constexpr const PointerType get_ptr() const noexcept;
9```
10
11Implicit pointer access to the internally stored JSON value. No copies are made.
12
13## Template parameters
14
15`PointerType`
16:   pointer type; must be a pointer to [`array_t`](array_t.md), [`object_t`](object_t.md), [`string_t`](string_t.md),
17    [`boolean_t`](boolean_t.md), [`number_integer_t`](number_integer_t.md), or
18    [`number_unsigned_t`](number_unsigned_t.md), [`number_float_t`](number_float_t.md), or [`binary_t`](binary_t.md).
19    Other types will not compile.
20
21## Return value
22
23pointer to the internally stored JSON value if the requested pointer type fits to the JSON value; `#!cpp nullptr`
24otherwise
25
26## Exception safety
27
28No-throw guarantee: this function never throws exceptions.
29
30## Complexity
31
32Constant.
33
34## Notes
35
36!!! danger "Undefined behavior"
37
38    Writing data to the pointee of the result yields an undefined state.
39
40## Examples
41
42??? example
43
44    The example below shows how pointers to internal values of a JSON value can be requested. Note that no type
45    conversions are made and a `#!cpp nullptr` is returned if the value and the requested pointer type does not match.
46
47    ```cpp
48    --8<-- "examples/get_ptr.cpp"
49    ```
50
51    Output:
52
53    ```json
54    --8<-- "examples/get_ptr.output"
55    ```
56
57## Version history
58
59- Added in version 1.0.0.
60- Extended to binary types in version 3.8.0.
61