NAME
mesg — enable or disable System V IPC messages at boot time
DESCRIPTION
The
mesg
tunable is obsolete. The System V IPC message subsystem is always enabled.
Overview
A System V message is just a sequence of bytes that can be passed
between cooperating processes via a message queue.
Messages can be of any length up to a tunable maximum.
Messages larger than 64 bytes (not tunable) are stored in one or more
contiguous "segments" of reserved kernel memory and are managed through
the message segment map.
Messages equal to or smaller than 64 bytes are allocated with the
message header and therefore do not consume a segment.
Each message is "typed" with an application-specific number.
Each message queue is referenced by a unique ID, and can contain
multiple individual messages.
The process receiving a message can get the "first" message (FIFO),
the first of a specified type, the first of a group of types, or wait
for a specific type to appear.
WARNINGS
Installation of optional kernel software, from HP or other vendors,
may cause changes to tunable parameter values. After installation,
some tunable parameters may no longer be at the default or
recommended values. For information about the effects of
installation on tunable values, consult the documentation
for the kernel software being installed.
For information about optional kernel software that was
factory installed on your system, see
HP-UX Release Notes
at
http://docs.hp.com.
AUTHOR
mesg
was developed by AT&T.
SEE ALSO
ipcrm(1),
ipcs(1),
msgctl(2),
msgget(2),
msgrcv(2),
msgsnd(2),
msgmap(5),
msgmax(5),
msgmnb(5),
msgmni(5),
msgseg(5),
msgssz(5),
msgtql(5).
