(This is the legacy documentation for SDL2, the previous stable version; SDL3 is the current stable version.)

SDL_LockSurface

Set up a surface for directly accessing the pixels.

Header File

Syntax

int SDL_LockSurface(SDL_Surface * surface);

Function Parameters

SDL_Surface *

surface

the SDL_Surface structure to be locked.

Return Value

(int) Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.

Remarks

Between calls to SDL_LockSurface() / SDL_UnlockSurface(), you can write to and read from surface->pixels, using the pixel format stored in surface->format. Once you are done accessing the surface, you should use SDL_UnlockSurface() to release it.

Not all surfaces require locking. If SDL_MUSTLOCK(surface) evaluates to 0, then you can read and write to the surface at any time, and the pixel format of the surface will not change.

Version

This function is available since SDL 2.0.0.