sem_close(2)sem_close(2)NAMEsem_close - close a named POSIX semaphore
SYNOPSISDESCRIPTION
is used to close a named semaphore. A successful call to will do the
following: Remove the process's descriptor for the semaphore referenced
by the specified structure sem. Remove the semaphore referenced by the
specified structure sem, if the semaphore is marked for removal by a
call to and there are no other descriptors referencing this semaphore.
When the process's descriptor for the semaphore referenced by sem is
removed, subsequent use of this semaphore by this process will fail.
Descriptors for named semaphores are also removed by processes on exit.
Calling does not affect other processes referencing the same semaphore.
To use this function, link in the realtime library by specifying on the
compiler or linker command line.
EXAMPLES
The following call to will close a named semaphore referred to by sem
by removing the process's descriptor to the semaphore and removing the
semaphore if it is marked for removal by a previous and there are no
descriptors referencing it.
RETURN VALUE
If the semaphore was closed and the descriptors referencing it were
removed, returns 0 to the caller.
If the semaphore could not be closed, the call returns -1 and sets to
indicate the error.
ERRORS
fails and does not perform the requested operation if the following
condition is encountered:
[EINVAL] The argument sem is not a valid named semaphore.
WARNINGS
A single call will make the semaphore unusable by the process no matter
how many times that process had called for the same semaphore. Subseā
quent calls to by the same process for the same semaphore will result
in an undefined behavior.
SEE ALSOsem_init(2), sem_open(2), sem_unlink(2), <semaphore.h>.
STANDARDS CONFORMANCEsem_close(2)