Collaboration diagram for Semaphore:
Detailed Description
Thread synchronization support.
In addition to posting and waiting for events, Threads can use the provided semaphore funxtions to handle a pool of shared resources.
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Data Structures |
| struct | _SEM |
| struct | _mutex |
| | Recursive mutex. More...
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Typedefs |
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typedef _SEM | SEM |
| | Sempahore type.
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Functions |
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void | NutSemInit (SEM *sem, short value) |
| | Initialize an unnamed semaphore to value.
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| void | NutSemWait (SEM *sem) |
| | Lock a semaphore.
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| int | NutSemTryWait (SEM *sem) |
| | Attempt to lock a semaphore without blocking.
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| void | NutSemPost (SEM *sem) |
| | Unlock a sempahore.
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| int | NutSemDestroy (SEM *sem) |
| | Free resources allocated for a semaphore.
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Function Documentation
| int NutSemDestroy |
( |
SEM * |
sem |
) |
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Free resources allocated for a semaphore.
Return zero, if successful, otherwise there are threads blocked on the sempahore |
| void NutSemPost |
( |
SEM * |
sem |
) |
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Unlock a sempahore.
: Should not be called from interrupt context |
| int NutSemTryWait |
( |
SEM * |
sem |
) |
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Attempt to lock a semaphore without blocking.
Return zero, if successful, otherwise the sempahore is already locked : Should not be called from interrupt context |
| void NutSemWait |
( |
SEM * |
sem |
) |
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Lock a semaphore.
If the semaphore value is currently zero, then the calling thread will not return from the call to sem_wait() the semaphore becomes available
: Should not be called from interrupt context |
