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

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       shmdt - 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 Defini-
       tions 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(3P)