json/docs/mkdocs/docs/api/basic_json/get_to.md

nlohmann::basic_json::get_to

template<typename ValueType>
ValueType& get_to(ValueType& v) const noexcept(
    noexcept(JSONSerializer<ValueType>::from_json(
        std::declval<const basic_json_t&>(), v)));

Explicit type conversion between the JSON value and a compatible value. The value is filled into the input parameter by calling the json_serializer<ValueType> from_json() method.

The function is equivalent to executing

ValueType v;
JSONSerializer<ValueType>::from_json(*this, v);

This overload is chosen if:

• ValueType is not basic_json,
• json_serializer<ValueType> has a from_json() method of the form void from_json(const basic_json&, ValueType&)

Template parameters

ValueType

the value type to return

Return value

the input parameter, allowing chaining calls

Exceptions

Depends on what json_serializer<ValueType> from_json() method throws

Complexity

Depends on the json_serializer<ValueType>::from_json() implementation.

Examples

??? example

The example below shows several conversions from JSON values to other types. There a few things to note: (1)
Floating-point numbers can be converted to integers, (2) A JSON array can be converted to a standard
`#!cpp std::vector<short>`, (3) A JSON object can be converted to C++ associative containers such as
`#cpp std::unordered_map<std::string, json>`.
    
```cpp
--8<-- "examples/get_to.cpp"
```

Output:

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

See also

• get get a value (explicit conversion)
• get_ref get a reference to the stored value
• get_ptr get a pointer to the stored value
• Converting values - the type conversions article

Version history

• Since version 3.3.0.