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Re: renaming a variable without making a copy [message #68919]

Wed, 09 December 2009 05:19

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

alx writes:
.
> Here is a question, maybe related to the previous one, regarding
> variable typecast in IDL.
> Changing the type of one scalar variable, even a vector, is fairly
> easy by using the FIX function.
> But let suppose that I get a variable (for instance from an external
> routine, by reading a shared memory,
> a socket, etc...) that is described as a vector of byte (or integer or
> float or anything else).
> I want to further consider this variable as a (elsewhere defined)
> structure (in the IDL sense).
> In other words, I want to typecast an untyped variable to a structured
> one : what is the way in IDL ?

There is no general way. Structures often have "hidden"
information inside them, mostly to align fields of data
with machine words, etc. Unless you know *exactly* how
a structure is built in whatever language you are dealing
with, it will be difficult to convert a stream of bytes
back into a structure on the IDL side of things. I've
heard of it being done, but I think it is fraught will
peril. :-)

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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[Message index]

		Re: renaming a variable without making a copy By: David Fanning on Wed, 09 December 2009 05:19
		Re: renaming a variable without making a copy By: lecacheux.alain on Wed, 09 December 2009 01:42
		Re: renaming a variable without making a copy By: David Fanning on Tue, 08 December 2009 14:39
		Re: renaming a variable without making a copy By: Michael Galloy on Tue, 08 December 2009 14:39
		Re: renaming a variable without making a copy By: Kenneth P. Bowman on Tue, 08 December 2009 13:51
		Re: renaming a variable without making a copy By: David Higgins on Tue, 08 December 2009 06:51
		Re: renaming a variable without making a copy By: David Fanning on Tue, 08 December 2009 05:18
		Re: renaming a variable without making a copy By: Kenneth P. Bowman on Wed, 09 December 2009 07:02
		Re: renaming a variable without making a copy By: R.Bauer on Wed, 09 December 2009 09:06
		Re: renaming a variable without making a copy By: lecacheux.alain on Wed, 09 December 2009 06:33

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