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* mkdocs: add string_view examples * mkdocs: reference underlying operators * mkdocs: add operator<=> examples * mkdocs: fix style check issues * mkdocs: tweak BJData page * mkdocs: add CMake option hints to macros * mkdocs: fix JSON_DISABLE_ENUM_SERIALIZATION definition * mkdocs: fix link to unit-udt.cpp * mkdocs: fix "Arbitrary Type Conversions" title * mkdocs: link to api/macros/*.md instead of features/macros.md * mkdocs: document JSON_DisableEnumSerialization CMake option * mkdocs: encode required C++ standard in example files * docset: detect gsed/sed * docset: update index * docset: fix CSS patching * docset: add list_missing_pages make target * docset: add list_removed_paths make target * docset: replace page titles with name from index * docset: add install target for Zeal docset browser * Use GCC_TOOL in ci_test_documentation target
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JSON_USE_IMPLICIT_CONVERSIONS
#define JSON_USE_IMPLICIT_CONVERSIONS /* value */
When defined to 0, implicit conversions are switched off. By default, implicit conversions are switched on. The
value directly affects operator ValueType.
Default definition
By default, implicit conversions are enabled.
#define JSON_USE_IMPLICIT_CONVERSIONS 1
Notes
!!! info "Future behavior change"
Implicit conversions will be switched off by default in the next major release of the library.
You can prepare existing code by already defining `JSON_USE_IMPLICIT_CONVERSIONS` to `0` and replace any implicit
conversions with calls to [`get`](../basic_json/get.md).
!!! hint "CMake option"
Implicit conversions can also be controlled with the CMake option
[`JSON_ImplicitConversions`](../../integration/cmake.md#json_legacydiscardedvaluecomparison)
(`ON` by default) which defines `JSON_USE_IMPLICIT_CONVERSIONS` accordingly.
Examples
??? example
This is an example for an implicit conversion:
```cpp
json j = "Hello, world!";
std::string s = j;
```
When `JSON_USE_IMPLICIT_CONVERSIONS` is defined to `0`, the code above does no longer compile. Instead, it must be
written like this:
```cpp
json j = "Hello, world!";
auto s = j.get<std::string>();
```
See also
- operator ValueType - get a value (implicit)
- get - get a value (explicit)
Version history
- Added in version 3.9.0.