Path: utzoo!utgpu!water!watmath!clyde!bellcore!decvax!decwrl!ucbvax!pasteur!ames!ncar!oddjob!gargoyle!att!ihnp4!cbmvax!carolyn
From: carolyn@cbmvax.UUCP (Carolyn Scheppner CATS)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Having trouble with the Execute() dos call
Keywords: AmigaBasic
Message-ID: <3862@cbmvax.UUCP>
Date: 24 May 88 22:35:16 GMT
References: <24869@bbn.COM>
Reply-To: carolyn@cbmvax.UUCP (Carolyn Scheppner CATS)
Organization: Commodore Technology, West Chester, PA
Lines: 58

In article <24869@bbn.COM> cosell@BBN.COM (Bernie Cosell) writes:
>Hi-
>  In the unlikely event that there's an AmigaBasic wizard out there some
>place, I thought I'd push my luck and try another inquiry about the mysteries
>of using the "real" libraries out of Basic.  This time, I'm doing battle
>with Execute&().  As I read the description of that call, it _seems_
>benign enough, but when I try to call it, my Amiga goes up in flames in
>all kinds of exciting ways -- of course, making it impossible to figure out
>what went wrong.  I tried something REAL simple like:
>   library "dos.library"
>   declare function Execute&() library
>   Execute& (sadd ("date > ram:junk"), 0&, 0&)
>Guru-central.  If I try the above with the "> ram:junk" left out, I
>assumed (with my eternal naivete) that date would inherit the "current"
>screen, which I hoped would be the basic screen.  No such luck, of
>course -- this time, I think it just made the machine stop dead in its
>tracks: no guru, nothing (wouldn't track the mouse or do ANYTHING).

Yes, you blew up your system by using the Execute() function, no doubt 
from within a program that was started from Workbench and therefore
had NO stdout.  Execute()ing a CLI command requires a CLI environment
or at least someplace for stdout to go.

You must use the dos.library Open() function (that's xOpen from AmigaBASIC
due to name conflict) to open some kind of file for Execute()'s output
to go to.  That file would generally be a CON:nn/... window or NIL:.

In addition - What's with the SADD("string") ????   I'd be real surprised
if that works.  In my experience YOU are responsible for null terminating your
amigabasic strings before passing them to a system call. (As below)

(P.S. - I am typing this in off the top of my head.  May not be exactly right
 but it's at least close)

DECLARE FUNCTION Execute&() LIBRARY
DECLARE FUNCTION xOpen&() LIBRARY

LIBRARY "dos.library"

outfile$ = "NIL:" + CHR$(0)
command$ = "date > ram:datefile" + CHR$(0)
modenew& = 1006

handle& = xOpen(SADD(outfile$),modenew&)

if(handle& > 0) then  
   success& = Execute(command&, 0&, outfile&)
   xClose(handle&)
endif

LIBRARY CLOSE

-- 
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Carolyn Scheppner -- CATS   >>Commodore Amiga Technical Support<<
                     UUCP  ...{allegra,ihnp4,rutgers}!cbmvax!carolyn 
                     PHONE 215-431-9180
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