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Re: Passing variables [message #55436]

Thu, 23 August 2007 08:39

Conor
Messages: 138
Registered: February 2007

Senior Member

On Aug 23, 11:33 am, jeffw...@hotmail.com wrote:
>> 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.

Oops! Sorry, that's my mistake (I only use common blocks
occasionally). The exact syntax is:

common share,A

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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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