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From: sirkm@ssyx.ucsc.edu (Greg Anderson)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: XCMD's cannot set global variables.
Message-ID: <3821@darkstar.ucsc.edu>
Date: 27 May 90 17:06:59 GMT
References: <3707@darkstar.ucsc.edu> <1266@urbana.mcd.mot.com>
Sender: usenet@darkstar.ucsc.edu
Reply-To: sirkm@ssyx.ucsc.edu (Greg Anderson)
Organization: UC Santa Cruz; Division of Social Sciences
Lines: 21

In article <1266@urbana.mcd.mot.com> willcox@urbana.mcd.mot.com (David A Willcox) writes:
>In article <3707@darkstar.ucsc.edu> I write:
>>I believe that the book "XCMD's for HyperCard" by Gary Bond mentions that
>>XCMDs cannot create global variables.
>
>Am I missing something?  I don't have any documentation available here
>at work, but I could swear that there are a pair of callbacks called
>something like GetGlobal() and SetGlobal() that let you get and set
>globals from an XCMD.  I've used them, and they work.

Yes, GetGlobal and SetGlobal exist and work fine, but in my experience,
strange things happen if the global variables do not exist before the
XCMD tries to Get or Set them.  (Strange things == the next XCMD that
gets the variable finds it empty.)

The best solution is to declare "Global foo" in some script that is always
executed before the XCMD is invoked.
  ___\    /___               Greg Anderson              ___\    /___ 
  \   \  /   /         Social Sciences Computing        \   \  /   /
   \  /\/\  /    University of California, Santa Cruz    \  /\/\  /
    \/    \/              sirkm@ssyx.ucsc.edu             \/    \/