###### (This is the documentation for SDL3, which is under heavy development and the API is changing! [SDL2](https://wiki.libsdl.org/SDL2/) is the current stable version!)
# SDL_GL_GetSwapInterval

Get the swap interval for the current OpenGL context.

## Header File

Defined in [SDL_video.h](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_video.h), but apps should use `#include <SDL3/SDL.h>`

## Syntax

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

```

## Function Parameters

|                  |                                                                                                                                                                                                                           |
| ---------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **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

Returns 0 on success or a negative error code 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.

## Version

This function is available since SDL 3.0.0.

## See Also

* [SDL_GL_SetSwapInterval](SDL_GL_SetSwapInterval)

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