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From: bruce@stride.UUCP (Bruce Robertson)
Newsgroups: net.bugs.4bsd
Subject: Question about 4.2BSD uprintf()
Message-ID: <559@stride.stride.UUCP>
Date: Fri, 21-Feb-86 12:45:12 EST
Article-I.D.: stride.559
Posted: Fri Feb 21 12:45:12 1986
Date-Received: Mon, 24-Feb-86 07:24:18 EST
Reply-To: bruce@stride.UUCP (Bruce Robertson)
Organization: Stride Micro, Reno, NV.
Lines: 16


I was wondering about something I saw in "subr_prf.c" in the 4.2 BSD
kernel sources.  The comments for the function uprintf() advertise that
you can call it from an interrupt routine to send a message to the
current user's terminal.  However, the code that finds out the user's
current terminal references u.u_ttyp.  This means that uprintf() will
print its message on the terminal of the *currently running* process.
Which process this is is essentially random, and almost always NOT the
process that caused the interrupt to occur.  I can't think of any
situation where you would want to actually call uprintf() from an
interrupt routine.  Any comments?
-- 

	Bruce Robertson
	UUCP: cbosgd!utah-cs!utah-gr!stride!bruce
	ARPA: stride!bruce@utah-gr.arpa