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From: STEINBERGER@SRI-KL.ARPA.UUCP
Newsgroups: mod.computers.vax
Subject: Terminal I/O during an AST
Message-ID: <12262534110.10.STEINBERGER@SRI-KL.ARPA>
Date: Sat, 13-Dec-86 15:31:41 EST
Article-I.D.: SRI-KL.12262534110.10.STEINBERGER
Posted: Sat Dec 13 15:31:41 1986
Date-Received: Mon, 15-Dec-86 23:35:06 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
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Approved: info-vax@sri-kl.arpa

I need to write to "my" terminal during some AST routines.  Page 3-26
of the uVAX Programming Manual warns of a possible "redundant I/O error"
if you use a FORTRAN write to the default output device (i.e.
WRITE(UNIT=*,....)).  A suggestion is made to open a channel to the terminal
and use it to avoid this problem.

I'm not clear on what this means.  Will an open statement like the following
do the trick?

OPEN(UNIT=NEW_LU,FILE="TT:",status='NEW',...)

Then use the NEW_LU in the AST for the FORTRAN reads and writes?


Or do I need something more involved like a SYS$ASSIGN call?  Then what should
be done with the assigned channel?  Use it in a SYS$QIOW call?

I would prefer not to lose any non-AST produced output to the screen that
may have been in progress when an AST that does a screen write occurs.
If it get's "split" into before-AST and after-AST portions, that's 
acceptible.

Thanks in advance to all who respond.


-Ric Steinberger
STEINBERGER@SRI-KL.ARPA

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