shmdt

SYNOPSIS
       #include <sys/shm.h>

       int shmdt(const void *shmaddr);


DESCRIPTION
       The  shmdt() function operates on XSI shared memory (see the Base Defi-
       nitions 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  inter-
       process  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
       Definitions volume of IEEE Std 1003.1-2001, <sys/shm.h>


IEEE/The Open Group                  2003                             SHMDT(P)