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shm_unlink(2) [osx man page]

SHM_UNLINK(2)						      BSD System Calls Manual						     SHM_UNLINK(2)

NAME
shm_unlink -- remove shared memory object SYNOPSIS
#include <sys/mman.h> int shm_unlink(const char *name); DESCRIPTION
The shm_unlink() function disassociates the shared memory object specified by name from that name. The resources associated with the shared memory object remain intact until the last file descriptor reference is removed, e.g., by close(2) or munmap(2), at which point the resources are reclaimed (if no references exist at the time of the call to shm_unlink(), the resources are reclaimed immediately). The name can only be reused when it is bound to a new shared memory object with a call to shm_open(2) with the O_CREAT flag. RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error, and the named shared memory object will remain unchanged. ERRORS
The shm_unlink() succeeds unless: [EACCES] Permission is denied to be remove the object. [ENAMETOOLONG] name exceeded the name size limit. This is currently PSHMNAMLEN characters (defined in <sys/posix_shm.h>), but this may change in the future. [ENOENT] The named object does not exist. SEE ALSO
close(2), mmap(2), munmap(2), shm_open(2), shmat(2), shmctl(2) HISTORY
shm_open() is specified in the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995). Darwin August 31, 2006 Darwin

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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)
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