sem_destroy(3C) Standard C Library Functions sem_destroy(3C)NAME
sem_destroy - destroy an unnamed semaphore
SYNOPSIS
#include <semaphore.h>
int sem_destroy(sem_t *sem);
DESCRIPTION
The sem_destroy() function is used to destroy the unnamed semaphore indicated by sem. Only a semaphore that was created using sem_init(3C)
may be destroyed using sem_destroy(); the effect of calling sem_destroy() with a named semaphore is undefined. The effect of subsequent use
of the semaphore sem is undefined until sem is re-initialized by another call to sem_init(3C).
It is safe to destroy an initialised semaphore upon which no threads are currently blocked. The effect of destroying a semaphore upon which
other threads are currently blocked is undefined.
RETURN VALUES
If successful, sem_destroy() returns 0, otherwise it returns -1 and sets errno to indicate the error.
ERRORS
The sem_destroy() function will fail if:
EINVAL The sem argument is not a valid semaphore.
The sem_destroy() function may fail if:
EBUSY There are currently processes (or LWPs or threads) blocked on the semaphore.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
|ATTRIBUTE TYPE |ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Committed |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
|Standard |See standards(5). |
+-----------------------------+-----------------------------+
SEE ALSO sem_init(3C), sem_open(3C), attributes(5), standards(5)SunOS 5.11 5 Feb 2008 sem_destroy(3C)
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sem_init(3RT) Realtime Library Functions sem_init(3RT)NAME
sem_init - initialize an unnamed semaphore
SYNOPSIS
cc [ flag... ] file... -lrt [ library... ]
#include <semaphore.h>
int sem_init(sem_t *sem, int pshared, unsigned int value);
DESCRIPTION
The sem_init() function is used to initialize the unnamed semaphore referred to by sem. The value of the initialized semaphore is value.
Following a successful call to sem_init(), the semaphore may be used in subsequent calls to sem_wait(3RT), sem_trywait(3RT), sem_post(3RT),
and sem_destroy(3RT). This semaphore remains usable until the semaphore is destroyed.
If the pshared argument has a non-zero value, then the semaphore is shared between processes; in this case, any process that can access the
semaphore sem can use sem for performing sem_wait(3RT), sem_trywait(3RT), sem_post(3RT), and sem_destroy(3RT) operations.
Only sem itself may be used for performing synchronization. The result of referring to copies of sem in calls to sem_wait(3RT), sem_try-
wait(3RT), sem_post(3RT), and sem_destroy(3RT), is undefined.
If the pshared argument is zero, then the semaphore is shared between threads of the process; any thread in this process can use sem for
performing sem_wait(3RT), sem_trywait(3RT), sem_post(3RT), and sem_destroy(3RT) operations. The use of the semaphore by threads other than
those created in the same process is undefined.
Attempting to initialize an already initialized semaphore results in undefined behavior.
RETURN VALUES
Upon successful completion, the function initializes the semaphore in sem. Otherwise, it returns -1 and sets errno to indicate the error.
ERRORS
The sem_init() function will fail if:
EINVAL The value argument exceeds SEM_VALUE_MAX.
ENOSPC A resource required to initialize the semaphore has been exhausted, or the resources have reached the limit on semaphores
(SEM_NSEMS_MAX).
ENOSYS The sem_init() function is not supported by the system.
EPERM The process lacks the appropriate privileges to initialize the semaphore.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO sem_destroy(3RT), sem_post(3RT), sem_wait(3RT), attributes(5), standards(5)SunOS 5.10 28 Jun 2002 sem_init(3RT)