DRAFT |
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
initial_value |
the starting value for the semaphore |
Return Value
Returns the semaphore or NULL if there was an error; call SDL_GetError() for more information.
*
Returns a pointer to an initialized semaphore or NULL if there was an error.
*
Code Examples
*
SDL_sem *my_sem;
my_sem = SDL_CreateSemaphore(INITIAL_SEM_VALUE);
if (my_sem == NULL) {
return CREATE_SEM_FAILED;
}
*
Should this example be merged with the one on the SDL_DestroySemaphore page and then used as an Include there instead?
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.
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