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

Evaluates to true if the surface needs to be locked before access.

## Header File

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

## Syntax

```c
#define SDL_MUSTLOCK(S) ((((S)->flags & SDL_SURFACE_LOCK_NEEDED)) == SDL_SURFACE_LOCK_NEEDED)
```

## Version

This macro is available since SDL 3.1.3.

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[CategoryAPI](CategoryAPI), [CategoryAPIMacro](CategoryAPIMacro), [CategorySurface](CategorySurface)