.\" $NetBSD: ttymsg.3,v 1.13 2013/01/16 06:44:27 wiz Exp $
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.Dd January 15, 2013
.Dt TTYMSG 3
.Os
.Sh NAME
.Nm ttymsg
.Nd ttymsg utility function
.Sh LIBRARY
.Lb libutil
.Sh SYNOPSIS
.In util.h
.Ft char *
.Fn ttymsg "struct iovec *iov" "int iovlen" "const char *tty" "int tmout"
.Sh DESCRIPTION
The
.Fn ttymsg
function is used by
programs such as
.Xr talkd 8 ,
.Xr syslogd 8 ,
.Xr wall 1 ,
etc., to display the contents of a uio structure on a terminal.
.Fn ttymsg
forks and finishes in the child if the write would block after
waiting up to
.Fa tmout
seconds.
.Sh RETURN VALUES
.Fn ttymsg
returns a pointer to an error string on unexpected
error; the string is not newline-terminated.
Various "normal" errors are
ignored (exclusive-use, lack of permission, etc.).
.Sh SEE ALSO
.Xr writev 2
.Sh BUGS
.Nm
could grow some flags and a username/uid who is the expected owner
of the tty.
If the flags say so then the owner should be checked against the tty
owner, and the message should not be sent if there is a mismatch.
Also another flag could say check against group writable, and don't
send a message.