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Re: JSYS calls under twenex maclisp
- To: David Vinayak Wallace <GUMBY at MIT-AI>
- Subject: Re: JSYS calls under twenex maclisp
- From: JonL at PARC-MAXC
- Date: Mon, 26 Jul 82 11:48:00 GMT
- Cc: INFO-LISP at MIT-AI, Zubkoff at CMU-20C, CSD.FREEMAN at SU-SCORE
- In-reply-to: GUMBY's message of 25 July 1982 20:02-EDT
- Original-date: 26 Jul 1982 04:48 PDT
How can I access values returned in random registers after a jsys call
(i.e "returns +1 if unsuccessful, error code in acc 2")?
The SUBFORK package, available with MacLisp on Twenex systems, has
a function JSYS which does just what you want.
(JSYS <jsys-number> <AC1> <AC2> <AC3> <ac-number-of-result>)
Thus the fifth argument tells which acumulator's contents to return as
the result of the JSYS call.
JSYS currently doesn't make any distinction between successful and
unsuccessful returns, but it could be fairly easily hacked in thru the
MULTIPLE-VALUE mechanism currently in MacLisp.
The SUBFORK package is primarily a "spin-off" of the MacLisp/EMACS
interface for Twenex users -- it provides a convenient way to run
other subsystems as a subfork of your MacLisp job. I'm not sure if it
ever got documented for general consumption, but there are several
little goodies in it that are probably of general interest.