SHMDT(P) POSIX Programmer's Manual SHMDT(P)
shmdt - XSI shared memory detach operation
int shmdt(const void *shmaddr);
The shmdt() function operates on XSI shared memory (see the Base Definitions 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
The shmdt() function detaches the shared memory segment located at the address specified
by shmaddr from the address space of the calling process.
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
Otherwise, the shared memory segment shall not be detached, shmdt() shall return -1, and
errno shall be set to indicate the error.
The shmdt() function shall fail if:
EINVAL The value of shmaddr is not the data segment start address of a shared memory seg-
The following sections are informative.
The POSIX Realtime Extension defines alternative interfaces for interprocess communica-
tion. 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.
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>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 SHMDT(P)