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| Use this function to create a semaphore, initialized with value, returns NULL on failure. <<Color2(green,Should this description stop at semaphore and the remaining info be moved below?)>> |
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*. |
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| Returns ^the current semaphore value for the resource^ on success, or NULL on failure; call [[SDL_GetError]]() for more information. | *<<BR>>Returns a pointer to an initialized semaphore or NULL if there was an error.<<BR>>* |
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| <<Color2(green,-OR- does it return a positive value when the resource is available and 0 when it is in use?)>> | ; call [[SDL_GetError]]() for more information. |
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| * | |
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| You can add your code example here | SDL_sem *my_sem; my_sem = SDL_CreateSemaphore(INITIAL_SEM_VALUE); if (my_sem == NULL) { return CREATE_SEM_FAILED; } |
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| * | |
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| ''You can add useful comments here'' | *<<BR>>[[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. <<BR>>* |
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| .[[SDL_DestroySemaphore]] ??? | .[[SDL_DestroySemaphore]] * .[[SDL_SemPost]] * .[[SDL_SemTryWait]] * .[[SDL_SemValue]] * .[[SDL_SemWait]] * .[[SDL_SemWaitTimeout]]* |
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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*.
Contents
Syntax
SDL_sem* SDL_CreateSemaphore(Uint32 initial_value)
Function Parameters
initial_value |
the starting value for the semaphore |
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.
*
