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Re: screwy system variables !? [2] [message #6698 is a reply to message #6602]

Fri, 26 July 1996 00:00

peter
Messages: 80
Registered: February 1994

Member

Chris Chase SRM (chase@custer.jhuapl.edu) wrote:
: >>>>> "Chad" == Chad Trujillo <trujillo@xnmusc.mit.edu> writes:
: In article <4t71d3$lhe@senator-bedfellow.MIT.EDU> trujillo@xnmusc.mit.edu (Chad Trujillo) writes:

: Chad> (Had some posting problems on the first one)
: Chad> It seems like I can't actually create new system variables in a
: Chad> function or program and use them later in that same function/program.
: Chad> For example, I have the following program (in file tester.pro):
: >> pro tester
: >> defsysv, "!tester", 222
: >> print, !tester ;this line directly refers to !tester
: >> end

: Chad> When I try to compile/run it, I get the following error (unless I
: Chad> manually define !tester at the command line first):
: >> % Not a legal system variable: !TESTER.

: The problem is that IDL creates references to variables at compile
: time, but the system variable !tester does not exist at compile time.
: It will not exist until the defsysv is executed at runtime.

: You will either need to perform the defsysv in another procedure that
: runs before this one is compiled or, as suggested by someone else, use
: an execute() statement wherever you reference the !tester (effectively
: execute() delays compilation until run time).

Does anybody regularly use system variables this way? Why? Why not a
regular variable in a common block?

Peter

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[Message index]

		screwy system variables !? [2] By: trujillo on Thu, 25 July 1996 00:00
		Re: screwy system variables !? [2] By: chase on Thu, 25 July 1996 00:00
		Re: screwy system variables !? By: thompson on Thu, 25 July 1996 00:00
		Re: screwy system variables !? [2] By: peter on Fri, 26 July 1996 00:00

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