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 correspond-
       ing 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 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 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 interprocess 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 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								 SHMDT(3P)