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MSG.H 3HEAD "Sep 10, 2004"
NAME
msg.h, msg - message queue structures
SYNOPSIS

#include <sys/msg.h>
DESCRIPTION

The <sys/msg.h> header defines the following data types through typedef: msgqnum_t

used for the number of messages in the message queue

msglen_t

used for the number of bytes allowed in the message queue

These types are unsigned integer types that are able to store values at least as large as a type unsigned short.

The <sys/msg.h> header defines the following constant as a message operation flag: MSG_NOERROR

no error if big message

The msqid_ds structure contains the following members:

struct ipc_perm msg_perm Operation permission structure.
msgqnum_t msg_qnum Number of messages currently on
 queue.
msglen_t msg_qbytes Maximum number of bytes allowed
 on queue.
pid_t msg_lspid Process ID of last msgsnd(2).
pid_t msg_lrpid Process ID of last msgrcv(2).
time_t msg_stime Time of last msgsnd().
time_t msg_rtime Time of last msgrcv().
time_t msg_ctime Time of last change.

The pid_t, time_t, key_t, size_t, and ssize_t types are defined as described in <sys/types.h>. See types(3HEAD).

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Standard
SEE ALSO

msgctl(2), msgget(2), msgrcv(2), msgsnd(2), ipc.h(3HEAD), types.h(3HEAD), attributes(5), standards(5)