shmdt(3p) — Linux manual page


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

PROLOG         top

       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         top

       shmdt — XSI shared memory detach operation

SYNOPSIS         top

       #include <sys/shm.h>

       int shmdt(const void *shmaddr);

DESCRIPTION         top

       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, 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         top

       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         top

       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         top



       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         top




SEE ALSO         top

       Section 2.7, XSI Interprocess Communication, Section 2.8, Realtime,
       exec(1p), exit(3p), fork(3p), shmat(3p), shmctl(3p), shmget(3p),
       shm_open(3p), shm_unlink(3p)

       The Base Definitions volume of POSIX.1‐2008, Section 3.342, Shared
       Memory Object, sys_shm.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- 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 Standard is the referee document. The original
       Standard can be obtained online at .

       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 .

IEEE/The Open Group                 2013                           SHMDT(3P)

Pages that refer to this page: sys_shm.h(0p)ipcs(1p)shmat(3p)shmctl(3p)shmget(3p)shm_open(3p)shm_unlink(3p)