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shmdt(3p) — Linux manual page

SHMDT(3P)               POSIX Programmer's ManualSHMDT(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

       Theshmdt() function operates on XSI shared memory (see the Base       Definitions volume of POSIX.1‐2017,Section 3.346,Shared MemoryObject).  It is unspecified whether this function interoperates       with the realtime interprocess communication facilities defined inSection 2.8,Realtime.       Theshmdt() function detaches the shared memory segment located at       the address specified byshmaddr from the address space of the       calling process.

RETURN VALUE        top

       Upon successful completion,shmdt() shall decrement the value ofshm_nattch in the data structure associated with the shared memory       ID of the attached shared memory segment and return 0. Also, theshm_dtime timestamp shall be set to the current time, as described       inSection 2.7.1,IPC General Description.       Otherwise, the shared memory segment shall not be detached,shmdt() shall return -1, anderrno shall be set to indicate the       error.

ERRORS        top

       Theshmdt() function shall fail if:EINVALThe value ofshmaddr 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 inSection 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,SharedMemory 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 athttp://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, seehttps://www.kernel.org/doc/man-pages/reporting_bugs.html .IEEE/The Open Group                2017SHMDT(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)

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