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Comment: update content (old wiki)
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Comment: update content - pointers, structs
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| ||'''sem'''||^a pointer to the SDL_sem structure / semaphore to be monitored^|| | ||'''sem'''||^the SDL_sem to be monitored^|| |
DRAFT |
SDL_SemWait
Use this function to suspend the calling thread until the semaphore pointed to by sem has a positive count, then atomically decrease the semaphore count -or- ...suspend the calling thread until the semaphore can be atomically decremented -or- *lock a semaphore and suspend the thread if the semaphore value is zero*.
Contents
Syntax
int SDL_SemWait(SDL_sem* sem)
Function Parameters
sem |
the SDL_sem to be monitored |
Return Value
Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.
If the semaphore was not successfully locked, the semaphore will be unchanged. ???
Code Examples
*
if (SDL_SemWait(my_sem) == -1) {
return WAIT_FAILED;
}
...
SDL_SemPost(my_sem);
*
Remarks
*
SDL_SemWait() 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.
After SDL_SemWait() is successful, the semaphore can be released and its count atomically incremented by a successful call to SDL_SemPost().
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