MSG.H(3HEAD) Headers MSG.H(3HEAD)

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(7) 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(7), standards(7)

September 10, 2004 MSG.H(3HEAD)