SDL_CreateSemaphore

Use this function to create a semaphore, initialized with ^a value _{returns NULL on failure} *create a new semaphore and assign an initial value to it*.

Syntax

SDL_sem* SDL_CreateSemaphore(Uint32 initial_value)

Function Parameters

Return Value

*
Returns a pointer to an initialized semaphore or NULL if there was an error.
*

; call SDL_GetError() for more information.

Code Examples

*

SDL_sem *my_sem;

my_sem = SDL_CreateSemaphore(INITIAL_SEM_VALUE);

if (my_sem == NULL) {
        return CREATE_SEM_FAILED;
}

*

Remarks

*
SDL_CreateSemaphore() creates a new semaphore and initializes it with the value initial_value. Each locking operation on the semaphore by SDL_SemWait(), SDL_SemTryWait() or SDL_SemWaitTimeout() will atomically decrement the semaphore value. The locking operation will be blocked if the semaphore value is not positive (greater than zero). Each unlock operation by SDL_SemPost() will atomically increment the semaphore value.
*

Related Functions

• SDL_DestroySemaphore *

• SDL_SemPost *

• SDL_SemTryWait *

• SDL_SemValue *

• SDL_SemWait *

• SDL_SemWaitTimeout*

CategoryAPI, CategoryMutex