SVR5 and SCO OpenServer 5
M_HANGUP, M_TRAIL --
report that the driver can no longer send data upstream
The M_HANGUP message type is
sent upstream by a driver to report
that it can no longer send data upstream.
This might be because of an error
or the dropping of a remote line connection.
When the message reaches the Stream head,
the Stream is marked so that all subsequent
system calls issued to the Stream
will fail and return an ENXIO error.
Those ioctls that cause messages to be sent downstream
are also failed.
POLLHUP is set if the Stream is being polled (see
Subsequent read or getmsg calls
to the Stream will not generate an error.
These calls will return any messages (according
to their function) that were on, or in transit to, the Stream head
read queue before the M_HANGUP message was received.
When all such messages have been read,
read returns 0,
and getmsg sets each of its two length fields to 0.
The M_HANGUP message
also causes a SIGHUP signal to
be sent to the process group
if the device is a controlling tty (see M_SIG).
The M_TRAIL message type marks the end of data
after an M_HANGUP message.
M_HANGUP is a priority message;
M_TRAIL is an ordinary message.
1, 2, 3, 4, 5, 5mp, 6, 6mp, 7, 7mp, 7.1, 7.1mp, 8, 8mp
For the M_HANGUP message type only,
1, 2, 2mp, 3, 3mp, 4, 4mp, 5, 5mp
Differences between versions
M_TRAIL is not implemented in ODDI.
19 June 2005
© 2005 The SCO Group, Inc. All rights reserved.
OpenServer 6 and UnixWare (SVR5) HDK - June 2005