1SHMDT(P)                   POSIX Programmer's Manual                  SHMDT(P)
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NAME

6       shmdt - XSI shared memory detach operation
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SYNOPSIS

9       #include <sys/shm.h>
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11       int shmdt(const void *shmaddr);
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DESCRIPTION

15       The  shmdt() function operates on XSI shared memory (see the Base Defi‐
16       nitions volume of IEEE Std 1003.1-2001, Section  3.340,  Shared  Memory
17       Object). It is unspecified whether this function interoperates with the
18       realtime interprocess communication facilities defined in Realtime .
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20       The shmdt() function detaches the shared memory segment located at  the
21       address  specified  by  shmaddr  from  the address space of the calling
22       process.
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RETURN VALUE

25       Upon successful  completion,  shmdt()  shall  decrement  the  value  of
26       shm_nattch  in  the data structure associated with the shared memory ID
27       of the attached shared memory segment and return 0.
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29       Otherwise, the shared memory segment shall  not  be  detached,  shmdt()
30       shall return -1, and errno shall be set to indicate the error.
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ERRORS

33       The shmdt() function shall fail if:
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35       EINVAL The  value of shmaddr is not the data segment start address of a
36              shared memory segment.
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39       The following sections are informative.
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EXAMPLES

42       None.
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APPLICATION USAGE

45       The POSIX Realtime Extension defines alternative interfaces for  inter‐
46       process  communication.  Application  developers  who  need  to use IPC
47       should design their applications so that modules using the IPC routines
48       described  in  XSI Interprocess Communication can be easily modified to
49       use the alternative interfaces.
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RATIONALE

52       None.
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FUTURE DIRECTIONS

55       None.
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SEE ALSO

58       XSI Interprocess Communication , Realtime , exec() , exit() , fork()  ,
59       shmat()  ,  shmctl()  , shmget() , shm_open() , shm_unlink() , the Base
60       Definitions volume of IEEE Std 1003.1-2001, <sys/shm.h>
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63       Portions of this text are reprinted and reproduced in  electronic  form
64       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
65       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
66       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
67       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
68       event of any discrepancy between this version and the original IEEE and
69       The Open Group Standard, the original IEEE and The Open Group  Standard
70       is  the  referee document. The original Standard can be obtained online
71       at http://www.opengroup.org/unix/online.html .
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75IEEE/The Open Group                  2003                             SHMDT(P)
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