1SHMDT(3P)                  POSIX Programmer's Manual                 SHMDT(3P)
2
3
4

PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
10

NAME

12       shmdt - XSI shared memory detach operation
13

SYNOPSIS

15       #include <sys/shm.h>
16
17       int shmdt(const void *shmaddr);
18
19

DESCRIPTION

21       The shmdt() function operates on XSI shared memory (see the Base  Defi‐
22       nitions  volume  of  IEEE Std 1003.1-2001, Section 3.340, Shared Memory
23       Object). It is unspecified whether this function interoperates with the
24       realtime interprocess communication facilities defined in Realtime .
25
26       The  shmdt() function detaches the shared memory segment located at the
27       address specified by shmaddr from the  address  space  of  the  calling
28       process.
29

RETURN VALUE

31       Upon  successful  completion,  shmdt()  shall  decrement  the  value of
32       shm_nattch in the data structure associated with the shared  memory  ID
33       of the attached shared memory segment and return 0.
34
35       Otherwise,  the  shared  memory  segment shall not be detached, shmdt()
36       shall return -1, and errno shall be set to indicate the error.
37

ERRORS

39       The shmdt() function shall fail if:
40
41       EINVAL The value of shmaddr is not the data segment start address of  a
42              shared memory segment.
43
44
45       The following sections are informative.
46

EXAMPLES

48       None.
49

APPLICATION USAGE

51       The  POSIX Realtime Extension defines alternative interfaces for inter‐
52       process communication. Application  developers  who  need  to  use  IPC
53       should design their applications so that modules using the IPC routines
54       described in XSI Interprocess Communication can be easily  modified  to
55       use the alternative interfaces.
56

RATIONALE

58       None.
59

FUTURE DIRECTIONS

61       None.
62

SEE ALSO

64       XSI  Interprocess  Communication,  Realtime,  exec()  , exit(), fork(),
65       shmat(), shmctl(), shmget(), shm_open(), shm_unlink(), the Base Defini‐
66       tions volume of IEEE Std 1003.1-2001, <sys/shm.h>
67

69       Portions  of  this text are reprinted and reproduced in electronic form
70       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
71       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
72       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
73       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
74       event of any discrepancy between this version and the original IEEE and
75       The  Open Group Standard, the original IEEE and The Open Group Standard
76       is the referee document. The original Standard can be  obtained  online
77       at http://www.opengroup.org/unix/online.html .
78
79
80
81IEEE/The Open Group                  2003                            SHMDT(3P)
Impressum