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Re: pointers in IDL [message #8805 is a reply to message #8800]

Mon, 28 April 1997 00:00

davidf
Messages: 2866
Registered: September 1996

Senior Member

Christian Oehreneder <co@ipf.tuwien.ac.at> writes:

> My application uses a not a priori known number of images with different
> sizes, which I want to access easily and flexible, preferrably by
> writing img_i = img(i) or something similar. Because of the different
> sizes of the images this is not easily done in IDL.
> In common programming lanuages it would be natural to have an array of
> pointers to each of the images.
> So far I have not found a possibilty to do this in IDL. Handles are nice
> but they do not allow to have two pointers on the same data. The effect
> is that once you take the value of a handle (without copying it of
> course !!) the handle itself contains an undefined value. It is not
> possible to have a list of images and pass them to some manipulation
> routines by pointer, e.g. multiplying all images by a factor of 2. Of
> course it is possible to take the value form the handle, multiply it and
> set it as value of the handle, but that's rather cumbersome.
>
> Has anyone an idea how to work arround this??

I think there is no good way to work around the cumbersome
method of handles except to upgrade to IDL 5.0 when it comes
out and take advantage of the new POINTER data type. I'm sure
it was added to the IDL language for exactly this reason.

Cheers!

David

----------------------------------------------------------
David Fanning, Ph.D.
Fanning Software Consulting
Customizable IDL Programming Courses
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com

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[Message index]

		Re: pointers in IDL By: Thomas A. McGlynn on Tue, 29 April 1997 00:00
		Re: pointers in IDL By: davidf on Mon, 28 April 1997 00:00
		Re: pointers in IDL By: rivers on Mon, 28 April 1997 00:00

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