trusty (3) shm_unlink.3posix.gz

Provided by: manpages-posix-dev_2.16-1_all bug

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>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard for Information Technology -- 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 .