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

SDL_CreateSemaphore

Create a semaphore.

Header File

Syntax

SDL_sem* SDL_CreateSemaphore(Uint32 initial_value);

Function Parameters

Uint32

initial_value

the starting value of the semaphore.

Return Value

(SDL_sem *) Returns a new semaphore or NULL on failure; call SDL_GetError() for more information.

Remarks

This function creates a new semaphore and initializes it with the value initial_value. Each wait operation on the semaphore will atomically decrement the semaphore value and potentially block if the semaphore value is 0. Each post operation will atomically increment the semaphore value and wake waiting threads and allow them to retry the wait operation.

Version

This function is available since SDL 2.0.0.