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⇤ ← Revision 1 as of 2010-06-02 01:17:01
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Comment: create page, add content (Wed Mar 10 ver; changeset 4428)
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Size: 2189
Comment: update content (old wiki)
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| Use this function ,,to,, ^as a^ variant of [[SDL_SemWait]]() with a timeout in milliseconds. | Use this function to *lock a semaphore* ^with a timeout^ ''-or-'' ^as a^ variant of [[SDL_SemWait]]() with a timeout in milliseconds. |
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| Returns 0 if the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in the allotted time, and -1 on error; call [[SDL_GetError]]() for more information. | Returns 0 if the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in the allotted time, or a negative error code on failure; call [[SDL_GetError]]() for more information. *<<BR>>If the semaphore was not successfully locked, the semaphore will be unchanged.<<BR>>* |
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| * | |
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| You can add your code example here | res = SDL_SemWaitTimeout(my_sem, WAIT_TIMEOUT_MILLISEC); if (res == SDL_MUTEX_TIMEDOUT) { return TRY_AGAIN; } if (res == -1) { return WAIT_ERROR; } ... SDL_SemPost(my_sem); |
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| *<<BR>><<Color2(green,Note that the 1.2 ver used a different param so this example should be checked for compliance with the current syntax.)>> | |
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| /!\ {i} On some platforms this function is implemented by looping with a delay of 1 ms, and so should be avoided if possible. | On some platforms this function is implemented by looping with a delay of 1 ms, and so should be avoided if possible. *<<BR>>[[SDL_SemWaitTimeout]]() is a variant of [[SDL_SemWait]]() with a maximum timeout value. If the value of the semaphore pointed to by '''sem''' is positive, it will atomically decrement the semaphore value and return 0, otherwise it will wait up to '''ms''' milliseconds trying to lock the semaphore. ,,This function is to be avoided if possible since on some platforms it is implemented by polling the semaphore every millisecond in a busy loop.,, After [[SDL_SemWaitTimeout]]() is successful, the semaphore can be released and its count atomically incremented by a successful call to [[SDL_SemPost]]().<<BR>>* |
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| .[[SDL_SemTryWait]] ??? .[[SDL_SemWait]] |
.[[SDL_SemPost]] * .[[SDL_SemTryWait]] * .[[SDL_SemValue]] * .[[SDL_SemWait]] * |
DRAFT |
SDL_SemWaitTimeout
Use this function to *lock a semaphore* with a timeout -or- as a variant of SDL_SemWait() with a timeout in milliseconds.
Contents
Syntax
int SDL_SemWaitTimeout(SDL_sem* sem,
Uint32 ms)
Function Parameters
sem |
a pointer to the SDL_sem structure to monitor |
ms |
the length of the timeout in milliseconds |
Return Value
Returns 0 if the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in the allotted time, 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
*
res = SDL_SemWaitTimeout(my_sem, WAIT_TIMEOUT_MILLISEC);
if (res == SDL_MUTEX_TIMEDOUT) {
return TRY_AGAIN;
}
if (res == -1) {
return WAIT_ERROR;
}
...
SDL_SemPost(my_sem);
*
green
Remarks
On some platforms this function is implemented by looping with a delay of 1 ms, and so should be avoided if possible.
*
SDL_SemWaitTimeout() is a variant of SDL_SemWait() with a maximum timeout value. If the value of the semaphore pointed to by sem is positive, it will atomically decrement the semaphore value and return 0, otherwise it will wait up to ms milliseconds trying to lock the semaphore. This function is to be avoided if possible since on some platforms it is implemented by polling the semaphore every millisecond in a busy loop.
After SDL_SemWaitTimeout() is successful, the semaphore can be released and its count atomically incremented by a successful call to SDL_SemPost().
*
