NAME
shmdt — XSI shared
memory detach operation
SYNOPSIS
int shmdt(const void *shmaddr);
DESCRIPTION
The shmdt () function operates on XSI
shared memory (see the Base Definitions volume of IEEE Std
1003.1-2001 (“POSIX.1”),
xbd_chap03(7)). It is unspecified whether this function
interoperates with the realtime interprocess communication facilities
defined in xsh_chap02_08(3).
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.
EXAMPLES
None.
APPLICATION USAGE
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 in xsh_chap02_07(3) can be easily modified to use the alternative interfaces.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
xsh_chap02_07(3), xsh_chap02_08(3), exec(3), exit(3), fork(3), shmat(3), shmctl(3), shmget(3), shm_open(3), shm_unlink(3), the Base Definitions volume of IEEE Std 1003.1-2001 (“POSIX.1”), <sys/shm.h>
CHANGE HISTORY
First released in Issue 2. Derived from Issue 2 of the SVID.
Issue 5
Moved from SHARED MEMORY to BASE.
The note about use of POSIX Realtime Extension IPC routines has been moved from FUTURE DIRECTIONS to a new APPLICATION USAGE section.
End of informative text. footer end