.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "SHMDT" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" shmdt 
.SH NAME
shmdt \- XSI shared memory detach operation
.SH SYNOPSIS
.LP
\fB#include <sys/shm.h>
.br
.sp
int shmdt(const void *\fP\fIshmaddr\fP\fB); \fP
\fB
.br
\fP
.SH DESCRIPTION
.LP
The \fIshmdt\fP() function operates on XSI shared memory (see the
Base Definitions 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 \fIRealtime\fP .
.LP
The \fIshmdt\fP() function detaches the shared memory segment located
at the address specified by \fIshmaddr\fP from the
address space of the calling process.
.SH RETURN VALUE
.LP
Upon successful completion, \fIshmdt\fP() shall decrement the value
of \fIshm_nattch\fP in the data structure associated with
the shared memory ID of the attached shared memory segment and return
0.
.LP
Otherwise, the shared memory segment shall not be detached, \fIshmdt\fP()
shall return -1, and \fIerrno\fP shall be set to
indicate the error.
.SH ERRORS
.LP
The \fIshmdt\fP() function shall fail if:
.TP 7
.B EINVAL
The value of \fIshmaddr\fP is not the data segment start address of
a shared memory segment.
.sp
.LP
\fIThe following sections are informative.\fP
.SH EXAMPLES
.LP
None.
.SH APPLICATION USAGE
.LP
The POSIX Realtime Extension defines alternative interfaces for interprocess
communication. Application developers who need to
use IPC should design their applications so that modules using the
IPC routines described in \fIXSI Interprocess Communication\fP can
be easily modified to use the alternative
interfaces.
.SH RATIONALE
.LP
None.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIXSI Interprocess Communication\fP , \fIRealtime\fP , \fIexec\fP()
,
\fIexit\fP() , \fIfork\fP() , \fIshmat\fP() , \fIshmctl\fP() , \fIshmget\fP()
, \fIshm_open\fP() , \fIshm_unlink\fP() , the Base Definitions volume
of IEEE\ Std\ 1003.1-2001, \fI<sys/shm.h>\fP
.SH 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 .