# SDL_IsMainThread

Return whether this is the main thread.

## Header File

Defined in [<SDL3/SDL_init.h>](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_init.h)

## Syntax

```c
bool SDL_IsMainThread(void);
```

## Return Value

(bool) Returns true if this thread is the main thread, or false otherwise.

## Remarks

On Apple platforms, the main thread is the thread that runs your program's
main() entry point. On other platforms, the main thread is the one that
calls [SDL_Init](SDL_Init)([SDL_INIT_VIDEO](SDL_INIT_VIDEO)), which should
usually be the one that runs your program's main() entry point. If you are
using the main callbacks, [SDL_AppInit](SDL_AppInit)(),
[SDL_AppIterate](SDL_AppIterate)(), and [SDL_AppQuit](SDL_AppQuit)() are
all called on the main thread.

## Thread Safety

It is safe to call this function from any thread.

## Version

This function is available since SDL 3.2.0.

## See Also

- [SDL_RunOnMainThread](SDL_RunOnMainThread)

----
[CategoryAPI](CategoryAPI), [CategoryAPIFunction](CategoryAPIFunction), [CategoryInit](CategoryInit)

