SHMDT(P) POSIX Programmer's Manual SHMDT(P)NAMEshmdt - XSI shared memory detach operation
SYNOPSIS
#include <sys/shm.h>
int shmdt(const void *shmaddr);
DESCRIPTION
The shmdt() function operates on XSI shared memory (see the Base Defi‐
nitions volume of IEEE Std 1003.1-2001, Section 3.340, Shared Memory
Object). It is unspecified whether this function interoperates with the
realtime interprocess communication facilities defined in Realtime .
The shmdt() function detaches the shared memory segment located at the
address specified by shmaddr from the address space of the calling
process.
RETURN VALUE
Upon successful completion, shmdt() shall decrement the value of
shm_nattch in the data structure associated with the shared memory ID
of the attached shared memory segment and return 0.
Otherwise, the shared memory segment shall not be detached, shmdt()
shall return -1, and errno shall be set to indicate the error.
ERRORS
The shmdt() function shall fail if:
EINVAL The value of shmaddr is not the data segment start address of a
shared memory segment.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
The POSIX Realtime Extension defines alternative interfaces for inter‐
process communication. Application developers who need to use IPC
should design their applications so that modules using the IPC routines
described in XSI Interprocess Communication can be easily modified to
use the alternative interfaces.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
XSI Interprocess Communication , Realtime , exec() , exit() , fork() ,
shmat() , shmctl() , shmget() , shm_open() , shm_unlink() , the Base
Definitions volume of IEEE Std 1003.1-2001, <sys/shm.h>
COPYRIGHT
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 .
IEEE/The Open Group 2003 SHMDT(P)
