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 POSIX.1-2008, Section 3.342, Shared Memory  Object).
       It is unspecified whether this function interoperates with the realtime interprocess communication facilities defined in Section 2.8, Real-
       time.

       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. Also, the shm_dtime timestamp shall be set to the current time, as  described  in  Section
       2.7.1, IPC General Description.

       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 Section 2.7, XSI  Interprocess  Communication  can	be
       easily modified to use the alternative interfaces.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       Section	2.7,  XSI  Interprocess  Communication,  Section  2.8,	Realtime,  exec,  exit(), fork(), shmat(), shmctl(), shmget(), shm_open(),
       shm_unlink()

       The Base Definitions volume of POSIX.1-2008, Section 3.342, Shared Memory Object, <sys_shm.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol-
       ogy  --	Portable  Operating  System  Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 Stan-
       dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE
/The Open Group						       2013								 SHMDT(3P)