35 lines
734 B
Markdown
35 lines
734 B
Markdown
# PR_WaitSemaphore
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Returns the value of the environment variable.
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## Syntax
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```{code}
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#include <pripcsem.h>
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NSPR_API(PRStatus) PR_WaitSemaphore(PRSem *sem);
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```
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### Parameter
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The function has the following parameter:
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`sem`
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: A pointer to a `PRSem` structure returned from a call to
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{ref}`PR_OpenSemaphore`.
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### Returns
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{ref}`PRStatus`
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## Description
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{ref}`PR_WaitSemaphore` tests the value of the semaphore. If the value of
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the semaphore is > 0, the value of the semaphore is decremented and the
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function returns. If the value of the semaphore is 0, the function
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blocks until the value becomes > 0, then the semaphore is decremented
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and the function returns.
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The "test and decrement" operation is performed atomically.
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