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trouble with pointers within array of structures [message #94442]

Tue, 23 May 2017 17:12

astroboy.20000
Messages: 39
Registered: August 2012

Member

I apologize for what I'm sure is a dumb question but I've looked all through the documentation for three days and I apparently am missing something.

I'm trying to store a pointer to a vector as an entry within a structure of arrays. This is the basic idea:

a = { name:'', image : ptr_new(/allocate) }
main = replicate(a,10)

;world() returns a 256x256 floating point image of the world,
;ct() returns a 256x256 floating point CT image

*main[5].image = world()
*main[4].image = ct()

tv, *main[4].image ;gives an image of the CT scan, which is what I expected
tv, *main[5].image ;gives an image of the CT scan
tv, *main[0].image ; ditto
tv, *main[9].image ; ditto

Obviously, I'm missing something fundamental about the syntax here but I've tried every permeation of parentheses and indices I can think of, and no matter what, the last pointer assigned overwrites every other pointer in the structure array.

Can anyone tell me what I should be doing here?

Thanks very much,

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[Message index]

		trouble with pointers within array of structures By: astroboy.20000 on Tue, 23 May 2017 17:12
		Re: trouble with pointers within array of structures By: wlandsman on Tue, 23 May 2017 18:12
		Re: trouble with pointers within array of structures By: Helder Marchetto on Tue, 23 May 2017 23:49
		Re: trouble with pointers within array of structures By: Markus Schmassmann on Wed, 24 May 2017 05:32
		Re: trouble with pointers within array of structures By: astroboy.20000 on Wed, 24 May 2017 06:59

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