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Re: Changing elements in structures [message #18315 is a reply to message #18301]

Wed, 15 December 1999 00:00

Liam Gumley
Messages: 473
Registered: November 1994

Senior Member

Alvaro wrote:
> I'm making a program that is a HDF viewer. My problem is how to pass
> information between widgets.
> I use a structure to pass the information but the problem is that at start I
> don't know the size of the data, which will be read later from a file. I use
> somethisg like this:
>
> info={filename:"", $
> data:IntArr(1,1) }
>
> I use IntAr(1,1) because I don't the size until I open the filename
> Can I change the size and also the type (Int to Float or Byte) of the tag
> "data" of the structure?

You cannot change the size of type of a variable in a structure without
re-creating the structure.

> Have you got any idea to do this, perhaps using pointers?

;- Define the structure
info = {filename:'', data_ptr:ptr_new(1.0)}

;- After you've read the data, store it in the structure
data = dist(256)
*info.data_ptr = data

;- Use the data
data = *info.data_ptr
tvscl, data

Cheers,
Liam.

--
Liam E. Gumley
Space Science and Engineering Center, UW-Madison
http://cimss.ssec.wisc.edu/~gumley

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[Message index]

		Re: Changing elements in structures By: m218003 on Thu, 16 December 1999 00:00
		Re: Changing elements in structures By: Liam Gumley on Wed, 15 December 1999 00:00
		Re: Changing elements in structures By: Karri Kaksonen on Wed, 15 December 1999 00:00

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