nlohmann::basic_json::get_ref

template<typename ReferenceType>
ReferenceType get_ref();

template<typename ReferenceType>
const ReferenceType get_ref() const;

Implicit reference access to the internally stored JSON value. No copies are made.

Template parameters

ReferenceType : reference type; must be a reference to array_t, object_t, string_t, boolean_t, number_integer_t, or number_unsigned_t, number_float_t, or binary_t. Enforced by a static assertion.

Return value

reference to the internally stored JSON value if the requested reference type fits to the JSON value; throws type_error.303 otherwise

Exception safety

Strong exception safety: if an exception occurs, the original value stays intact.

Exceptions

Throws type_error.303 if the requested reference type does not match the stored JSON value type; example: "incompatible ReferenceType for get_ref, actual type is binary".

Complexity

Constant.

Notes

!!! danger “Undefined behavior”

Writing data to the referee of the result yields an undefined state.

Examples

??? example

The example shows several calls to `get_ref()`.

```cpp
--8<-- "examples/get_ref.cpp"
```

Output:

```json
--8<-- "examples/get_ref.output"
```

Version history

• Added in version 1.1.0.
• Extended to binary types in version 3.8.0.