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Re: Passing variables [message #55437 is a reply to message #55436]

Thu, 23 August 2007 08:33

jeffwax1
Messages: 10
Registered: June 2004

Junior Member

> The easiest way is typically to use a common block. At the start of
> everyone program that want to access some variables, put a line like
> this:
>
> common, block_name, variable1, variable2, ....
>
> A couple rules about common blocks:
>
> 1) The names of the variables don't have to be the same in every
> program.
> 2) The number of variables matter. All common blocks should have the
> same number of variables.
> 3) The positions of the variables matter. Since names don't matter,
> the first variable in one program will always be the same as the first
> variable in another program, even if they have much different names
> 4) Common blocks last until you quit IDL. If you declare it once, it
> stays declared.
> 5) Common blocks can't be extended. This means that if you create a
> common block and later realize you need to add more variables to it,
> you'll have to quit IDL (or type .reset) in order to "destroy" the
> common block.

In the help files the only examples I see of common blocks are inside
procedures. Can I put them inside a function, or even my main
program? I tried putting:

common, share, B

in both my main program and the program with the function I'm using,
and both came back as syntax errors.

On second thought, after trying to answer my own program, I made a
test program along the lines of:

pro test
common, share, A

...

end

IDL is insisting that the "common,share,A" is a syntax error.

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[Message index]

		Re: Passing variables By: Conor on Thu, 23 August 2007 08:39
		Re: Passing variables By: jeffwax1 on Thu, 23 August 2007 08:33
		Re: Passing variables By: David Fanning on Thu, 23 August 2007 06:43
		Re: Passing variables By: Conor on Thu, 23 August 2007 06:34
		Re: Passing variables By: David Fanning on Thu, 23 August 2007 08:59
		Re: Passing variables By: jeffwax1 on Thu, 23 August 2007 08:55

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