json/api/macros/json_skip_library_version_check.md

JSON_SKIP_LIBRARY_VERSION_CHECK

#define JSON_SKIP_LIBRARY_VERSION_CHECK

When defined, the library will not create a compiler warning when a different version of the library was already included.

Default definition

By default, the macro is not defined.

#undef JSON_SKIP_LIBRARY_VERSION_CHECK

Notes

!!! danger "ABI compatibility"

Mixing different library versions in the same code can be a problem as the different versions may not be ABI
compatible.

Examples

??? example

The code below switches off the warning about including a different version of the library.

```cpp
#define JSON_SKIP_LIBRARY_VERSION_CHECK 1
#include <nlohmann/json.hpp>

...
```

!!! example

The following warning will be shown in case a different version of the library was already included:

```
Already included a different version of the library!
```

Version history

Added in version 3.11.0.