shm_unlink(3p) [centos man page]

SHM_UNLINK(3P)						     POSIX Programmer's Manual						    SHM_UNLINK(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       shm_unlink - remove a shared memory object (REALTIME)

SYNOPSIS

       #include <sys/mman.h>

       int shm_unlink(const char *name);

DESCRIPTION

       The shm_unlink() function shall remove the name of the shared memory object named by the string pointed to by name.

       If one or more references to the shared memory object exist when the object is unlinked, the name  shall  be  removed  before  shm_unlink()
       returns,  but  the  removal  of the memory object contents shall be postponed until all open and map references to the shared memory object
       have been removed.

       Even if the object continues to exist after the last shm_unlink(), reuse of the name shall subsequently cause shm_open() to behave as if no
       shared memory object of this name exists (that is, shm_open() will fail if O_CREAT is not set, or will create a new shared memory object if
       O_CREAT is set).

RETURN VALUE

       Upon successful completion, a value of zero shall be returned. Otherwise, a value of -1 shall be returned and errno  set  to  indicate  the
       error. If -1 is returned, the named shared memory object shall not be changed by this function call.

ERRORS

       The shm_unlink() function shall fail if:

       EACCES Permission is denied to unlink the named shared memory object.

       ENAMETOOLONG
	      The length of the name argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.

       ENOENT The named shared memory object does not exist.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       Names  of  memory objects that were allocated with open() are deleted with unlink() in the usual fashion. Names of memory objects that were
       allocated with shm_open() are deleted with shm_unlink(). Note that the actual memory object is not destroyed until the last close and unmap
       on it have occurred if it was already in use.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       close(), mmap(), munmap(), shmat(), shmctl(), shmdt(), shm_open(), the Base Definitions volume of IEEE Std 1003.1-2001, <sys/mman.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical  and	Electronics  Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
       and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can  be  obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003							    SHM_UNLINK(3P)

Check Out this Related Man Page

shm_unlink(3RT) 					    Realtime Library Functions						   shm_unlink(3RT)

NAME

       shm_unlink - remove a shared memory object

SYNOPSIS

       cc [ flag... ] file... -lrt [ library... ]
       #include <sys/mman.h>

       int shm_unlink(const char *name);

DESCRIPTION

       The shm_unlink() function removes the name of the shared memory object named by the string pointed to by name. If one or more references to
       the shared memory object exists when the object is unlinked, the name is removed before shm_unlink() returns, but the removal of the memory
       object contents will be postponed until all open and mapped references to the shared memory object have been removed.

RETURN VALUES

       Upon  successful  completion, shm_unlink() returns 0. Otherwise it returns -1 and sets errno to indicate the error condition, and the named
       shared memory object is not affected by this function call.

ERRORS

       The  shm_unlink() function will fail if:

       EACCES		       Permission is denied to unlink the named shared memory object.

       ENAMETOOLONG	       The length of the name  string  exceeds	 PATH_MAX,  or	a  pathname  component	is  longer  than   NAME_MAX  while
			       _POSIX_NO_TRUNC is in effect.

       ENOENT		       The named shared memory object does not exist.

       ENOSYS		       The shm_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

       close(2), mmap(2), mlock(3C), shm_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 						   shm_unlink(3RT)

Linux and UNIX Man Pages

shm_unlink(3p) [centos man page]

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