====== (This is the legacy documentation for stable SDL2, the current stable version; [https://wiki.libsdl.org/SDL3/ SDL3] is the current development version.) ======
= SDL_MUSTLOCK =

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

== Header File ==

Defined in [SDL_surface.h](https://github.com/libsdl-org/SDL/blob/SDL2/include/SDL_surface.h), but apps should _only_ `#include "SDL.h"`!

== Syntax ==

<syntaxhighlight lang='c'>
#define SDL_MUSTLOCK(S) (((S)->flags & SDL_RLEACCEL) != 0)</syntaxhighlight>

----
[[CategoryAPI]], [[CategoryAPIMacro]], [[CategorySurface]]