shmdt(3p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

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.1‐2017, Section 3.346, 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

       None.

APPLICATION USAGE         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

       None.

FUTURE DIRECTIONS         top

       None.

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.1‐2017, Section 3.346, Shared
       Memory Object, sys_shm.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 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 .

       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                2017                         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)