get message queue
int msgget(key_t key, int msgflg);
msgget returns the message queue identifier associated with
This identifier is accessible by any process in the system,
subject to normal access restrictions
and the permissions set with msgflg.
A successful call to msgget does not imply access to the
queue in question, only a successful name mapping from
A message queue identifier and associated message queue and data structure
are created for key
if one of the following are true:
does not already have a message queue identifier associated with it, and
On creation, the data structure associated with the new message queue
identifier is initialized as follows:
msg_perm.cgid, and msg_perm.gid
are set to the effective user ID
and effective group ID,
respectively, of the calling process.
The low-order 9 bits of
are set to the low-order 9 bits of
msg_qnum, msg_lspid, msg_lrpid,
msg_stime, and msg_rtime
are set to 0.
is set to the current time.
is set to the system limit.
On success, msgget returns a non-negative integer, namely a message queue identifier.
On failure, msgget returns -1 and sets errno to identify the error.
In the following conditions, msgget fails and sets errno to:
A message queue identifier exists for
but the queue was not created supporting the specified operation
A message queue identifier does not exist for
key and (msgflg&IPC_CREAT) is false.
A message queue identifier is to be created but
the system-imposed limit on the maximum number of
allowed message queue identifiers system wide
would be exceeded.
A message queue identifier exists for key
but (msgflg&IPC_CREAT) and (msgflg&IPC_EXCL)
are both true.
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004