[comp.os.vms] Modifying Print Symbionts.

T_WADE@CSVAX.UCD.HEA.IRL (08/21/87)

I would be interested in hearing from anyone who has written a user output
routine to replace the main output routine in the print symbiont. I have
done this, but the symbiont exits with an access violation AFTER my output
routine has successfully completed with SS$_NORMAL for the first output
record. I would like to see a working output routine to see if there is
anything I am misunderstanding.

Many thanks.
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Tom Wade                      Hea:      twade@ccvax.ucd.hea.irl
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tli@sargas.usc.edu (Tony Li) (08/22/87)

We have a working (but not completely bug-free) modified symbiont that
is written in C.

The best way of writing/debugging this type of problem is to set
yourself up so that you can use the debugger.  The modified symbiont
is run as part of a detached process.  By reassigning DBG$INPUT and
DBG$OUTPUT (in the system table), you can run the debugger on it and
yes, even see source.

By the way, before you ask, our print symbiont does something very
site-specific.

;-)
Tony Li - USC University Computing Services	"Fene mele kiki bobo"
Uucp: oberon!tli						-- Joe Isuzu
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Internet: tli@sargas.usc.edu