1 .\" $NetBSD: msgsnd.2,v 1.1 1995/10/16 23:49:24 jtc Exp $
3 .\" Copyright (c) 1995 Frank van der Linden
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39 .Nd send a message to a message queue
47 .Fn msgsnd "int msqid" "const void *msgp" "size_t msgsz" "int msgflg"
51 function sends a message to the message queue specified in
56 points to a structure containing the message.
58 consist of the following members:
60 long mtype; /* message type */
61 char mtext[1]; /* body of message */
65 is an integer greater than 0 that can be used for selecting messages (see
73 can range from 0 to a system-imposed maximum,
76 If the number of bytes already on the message queue plus
78 is bigger than the maximum number of bytes on the message queue
82 or the number of messages on all queues system-wide is already equal to
85 determines the action of
91 mask set in it, the call will return immediately.
96 set in it, the call will block until:
99 The condition which caused the call to block does no longer exist.
100 The message will be sent.
102 The message queue is removed, in which case -1 will be returned, and
107 The caller catches a signal.
108 The call returns with
114 After a successful call, the data structure associated with the message
115 queue is updated in the following way:
119 is incremented by the size of the message.
125 is set to the pid of the calling process.
128 is set to the current time.
142 is not a valid message queue identifier.
144 The message queue was removed while
146 was waiting for a resource to become available in order to deliver the
158 is not greater than 0.
160 The calling process does not have write access to the message queue.
162 There was no space for this message either on the queue, or in the whole
171 points to an invalid address.
173 The system call was interrupted by the delivery of a signal.
176 Message queues appeared in the first release of AT&T Unix System V.
183 error value, which should be used
184 in the case of a removed message queue.