sem_close(3) [osf1 man page]
sem_close(3) Library Functions Manual sem_close(3) NAME
sem_close - Deallocates the specified named semaphore (P1003.1b) LIBRARY
Realtime Library (librt.so, librt.a) SYNOPSIS
#include <semaphore.h> int sem_close ( sem_t *sem) ; PARAMETERS
sem References the semaphore to be closed. Use the sem argument returned by the previous call to sem_open. DESCRIPTION
The sem_close function makes a semaphore available for reuse by deallocating any system resources allocated for use by the current process for the named semaphore indicated by sem. If the semaphore has not been removed with a call to sem_unlink, sem_close does not change the current state of the semaphore. If the semaphore has been removed with a call to sem_unlink after the most recent call to sem_open with O_CREAT, the semaphore is no longer available after all processes that opened the semaphore close it. RETURN VALUES
On a successful call, a value of 0 (zero) is returned. Otherwise, a value of -1 is returned and errno is set to indicate that an error occurred. ERRORS
The sem_close function fails under the following condition: [EINVAL] The sem argument is not a valid semaphore descriptor. RELATED INFORMATION
Functions: sem_init(3), sem_open(3), sem_unlink(3) Guide to Realtime Programming delim off sem_close(3)
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sem_close(3C) Standard C Library Functions sem_close(3C) NAME
sem_close - close a named semaphore SYNOPSIS
#include <semaphore.h> int sem_close(sem_t *sem); DESCRIPTION
The sem_close() function is used to indicate that the calling process is finished using the named semaphore indicated by sem. The effects of calling sem_close() for an unnamed semaphore (one created by sem_init(3C)) are undefined. The sem_close() function deallocates (that is, make available for reuse by a subsequent sem_open(3C) by this process) any system resources allocated by the system for use by this process for this semaphore. The effect of subsequent use of the semaphore indicated by sem by this process is undefined. If the semaphore has not been removed with a successful call to sem_unlink(3C), then sem_close() has no effect on the state of the semaphore. If the sem_unlink(3C) function has been successfully invoked for name after the most recent call to sem_open(3C) with O_CREAT for this semaphore, then when all processes that have opened the semaphore close it, the semaphore is no longer be accessible. RETURN VALUES
If successful, sem_close() returns 0, otherwise it returns -1 and sets errno to indicate the error. ERRORS
The sem_close() function will fail if: EINVAL The sem argument is not a valid semaphore descriptor. ENOSYS The sem_close() function is not supported by the system. USAGE
The sem_close() function should not be called for an unnamed semaphore initialized by sem_init(3C). 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), sem_unlink(3C), attributes(5), standards(5) NOTES
Solaris 2.6 was the first release to support the Asynchronous Input and Output option. Prior to this release, this function always returned -1 and set errno to ENOSYS. SunOS 5.11 5 Feb 2008 sem_close(3C)