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NAMEmsgsnd —
send a message to a message queue
LIBRARYStandard C Library (libc, -lc)SYNOPSIS#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
int
DESCRIPTIONThemsgsnd () function sends a message to the message
queue specified in msqid. The msgp
argument points to a structure containing the message. This structure should
consist of the following members:
long mtype; /* message type */ char mtext[1]; /* body of message */ mtype is an integer greater than 0 that can
be used for selecting messages (see
msgrcv(2)),
mtext is an array of msgsz
bytes. The argument msgsz can range from 0 to a
system-imposed maximum, If the number of bytes already on the message queue plus
msgsz is bigger than the maximum number of bytes on
the message queue (msg_qbytes, see
msgctl(2)),
or the number of messages on all queues system-wide is already equal to the
system limit, msgflg determines the action of
After a successful call, the data structure associated with the message queue is updated in the following way:
RETURN VALUESThemsgsnd () function returns the value 0 if
successful; otherwise the value -1 is returned and the global variable
errno is set to indicate the error.
ERRORSThemsgsnd () function will fail if:
HISTORYMessage queues appeared in the first release of AT&T Unix System V.BUGSNetBSD and FreeBSD do not define theEIDRM error value, which should be used in the
case of a removed message queue.
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