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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

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.

CMake option

Implicit conversions can also be controlled with the CMake option JSON_ImplicitConversions (ON by default) which defines JSON_USE_IMPLICIT_CONVERSIONS accordingly.

Examples

Example

This is an example for an implicit conversion:

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:

json j = "Hello, world!";
auto s = j.get<std::string>();

See also

Version history

  • Added in version 3.9.0.

Last update: September 18, 2022