###### (This is the documentation for SDL3, which is the current stable version. [SDL2](https://wiki.libsdl.org/SDL2/) was the previous version!)
# SDL_GL_GetSwapInterval

Get the swap interval for the current OpenGL context.

## Header File

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

## Syntax

```c
bool SDL_GL_GetSwapInterval(int *interval);
```

## Function Parameters

|       |              |                                                                                                                                                                                                                            |
| ----- | ------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| int * | **interval** | output interval value. 0 if there is no vertical retrace synchronization, 1 if the buffer swap is synchronized with the vertical retrace, and -1 if late swaps happen immediately instead of waiting for the next retrace. |

## Return Value

(bool) Returns true on success or false on failure; call
[SDL_GetError](SDL_GetError)() for more information.

## Remarks

If the system can't determine the swap interval, or there isn't a valid
current context, this function will set *interval to 0 as a safe default.

## Thread Safety

This function should only be called on the main thread.

## Version

This function is available since SDL 3.1.3.

## See Also

- [SDL_GL_SetSwapInterval](SDL_GL_SetSwapInterval)

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