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

SDL_SemWait

Wait until a semaphore has a positive value and then decrements it.

Header File

Syntax

int SDL_SemWait(SDL_sem * sem);

Function Parameters

sem

the semaphore wait on

Return Value

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

Remarks

This function suspends the calling thread until either the semaphore pointed to by sem has a positive value or the call is interrupted by a signal or error. If the call is successful it will atomically decrement the semaphore value.

This function is the equivalent of calling SDL_SemWaitTimeout() with a time length of SDL_MUTEX_MAXWAIT.

Version

This function is available since SDL 2.0.0.