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← Revision 5 as of 2013-08-12 05:44:22 ⇥
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| Deletions are marked like this. | Additions are marked like this. |
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| #pragma disable-camelcase ||<tablewidth="100%" style="color: #FF0000;" :> DRAFT|| |
#pragma camelcase off |
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| ||'''sem'''||^the semaphore to destroy^|| | ||'''sem'''||the semaphore to destroy|| |
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| {{{#!highlight cpp if (my_sem != NULL) { SDL_DestroySemaphore(my_sem); my_sem = NULL; } }}} |
<<Include(SDL_CreateSemaphore, , , from="## Begin Semaphore Example", to="## End Semaphore Example")>> |
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| *<<BR>>It is not safe to destroy a semaphore if there are threads currently ,,blocked,, waiting on it. <<BR>>* | It is not safe to destroy a semaphore if there are threads currently waiting on it. |
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| .[[SDL_CreateSemaphore]] * <<Color2(green,The old wiki lists the other Sem functions as RFs.)>> |
.[[SDL_CreateSemaphore]] .[[SDL_SemPost]] .[[SDL_SemTryWait]] .[[SDL_SemValue]] .[[SDL_SemWait]] .[[SDL_SemWaitTimeout]] |
SDL_DestroySemaphore
Use this function to destroy a semaphore.
Syntax
void SDL_DestroySemaphore(SDL_sem* sem)
Function Parameters
sem |
the semaphore to destroy |
Code Examples
Typical use of semaphores:
SDL_atomic_t done;
SDL_sem *sem;
SDL_AtomicSet(&done, 0);
sem = SDL_CreateSemaphore(0);
.
.
Thread A:
while (!SDL_AtomicGet(&done)) {
add_data_to_queue();
SDL_SemPost(sem);
}
Thread B:
while (!SDL_AtomicGet(&done)) {
SDL_SemWait(sem);
if (data_available()) {
get_data_from_queue();
}
}
.
.
SDL_AtomicSet(&done, 1);
SDL_SemPost(sem);
wait_for_threads();
SDL_DestroySemaphore(sem);
Remarks
It is not safe to destroy a semaphore if there are threads currently waiting on it.
