sem_unlink(3rt) [sunos man page]
sem_unlink(3RT) Realtime Library Functions sem_unlink(3RT) NAME
sem_unlink - remove a named semaphore SYNOPSIS
cc [ flag... ] file... -lrt [ library... ] #include <semaphore.h> int sem_unlink(const char *name); DESCRIPTION
The sem_unlink() function removes the semaphore named by the string name. If the semaphore named by name is currently referenced by other processes, then sem_unlink() has no effect on the state of the semaphore. If one or more processes have the semaphore open when sem_unlink() is called, destruction of the semaphore is postponed until all references to the semaphore have been destroyed by calls to sem_close(3RT), _exit(2), or one of the exec functions (see exec(2)) . Calls to sem_open(3RT) to re-create or re-connect to the semaphore refer to a new semaphore after sem_unlink() is called. The sem_unlink() call does not block until all references have been destroyed; it returns immediately. RETURN VALUES
Upon successful completion, sem_unlink() returns 0. Otherwise, the semaphore is not changed and the function returns a value of -1 and sets errno to indicate the error. ERRORS
The sem_unlink() function will fail if: EACCES Permission is denied to unlink the named semaphore. ENAMETOOLONG The length of name string exceeds PATH_MAX, or a pathname component is longer than NAME_MAX while _POSIX_NO_TRUNC is in effect. ENOENT The named semaphore does not exist. ENOSYS The sem_unlink() function is not supported by the system. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
exec(2), exit(2), sem_close(3RT), sem_open(3RT), 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 5.10 28 Jun 2002 sem_unlink(3RT)
Check Out this Related Man Page
SEM_OPEN(3) BSD Library Functions Manual SEM_OPEN(3) NAME
sem_open, sem_close, sem_unlink -- named semaphore operations LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <semaphore.h> sem_t * sem_open(const char *name, int oflag, ...); int sem_close(sem_t *sem); int sem_unlink(const char *name); DESCRIPTION
The sem_open() function creates or opens the named semaphore specified by name. The returned semaphore may be used in subsequent calls to sem_getvalue(3), sem_wait(3), sem_trywait(3), sem_post(3), and sem_close(). This implementation places strict requirements on the value of name: it must begin with a slash ('/') and contain no other slash characters. The following bits may be set in the oflag argument: O_CREAT Create the semaphore if it does not already exist. The third argument to the call to sem_open() must be of type mode_t and specifies the mode for the semaphore. Only the S_IWUSR, S_IWGRP, and S_IWOTH bits are examined; it is not possible to grant only ``read'' permission on a semaphore. The mode is modified according to the process's file creation mask; see umask(2). The fourth argument must be an unsigned int and specifies the initial value for the semaphore, and must be no greater than SEM_VALUE_MAX. O_EXCL Create the semaphore if it does not exist. If the semaphore already exists, sem_open() will fail. This flag is ignored unless O_CREAT is also specified. The sem_close() function closes a named semaphore that was opened by a call to sem_open(). The sem_unlink() function removes the semaphore named name. Resources allocated to the semaphore are only deallocated when all processes that have the semaphore open close it. RETURN VALUES
If successful, the sem_open() function returns the address of the opened semaphore. If the same name argument is given to multiple calls to sem_open() by the same process without an intervening call to sem_close(), the same address is returned each time. If the semaphore cannot be opened, sem_open() returns SEM_FAILED and the global variable errno is set to indicate the error. The sem_close() and sem_unlink() functions return the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS
The sem_open() function will fail if: [EACCES] The semaphore exists and the permissions specified by oflag at the time it was created deny access to this process. [EACCES] The semaphore does not exist, but permission to create it is denied. [EEXIST] O_CREAT and O_EXCL are set but the semaphore already exists. [EINTR] The call was interrupted by a signal. [EINVAL] The sem_open() operation is not supported for the given name. [EINVAL] The value argument is greater than SEM_VALUE_MAX. [ENAMETOOLONG] The name argument is too long. [ENFILE] The system limit on semaphores has been reached. [ENOENT] O_CREAT is not set but the named semaphore does not exist. [ENOSPC] There is not enough space to create the semaphore. The sem_close() function will fail if: [EINVAL] The sem argument is not a valid semaphore. The sem_unlink() function will fail if: [EACCES] Permission is denied to unlink the semaphore. [ENAMETOOLONG] The specified name is too long. [ENOENT] The named semaphore does not exist. SEE ALSO
close(2), open(2), umask(2), unlink(2), sem_getvalue(3), sem_post(3), sem_trywait(3), sem_wait(3) STANDARDS
The sem_open(), sem_close(), and sem_unlink() functions conform to ISO/IEC 9945-1:1996 (``POSIX.1''). HISTORY
Support for named semaphores first appeared in FreeBSD 5.0. BSD
January 9, 2010 BSD