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Re: pointer question [message #24322 is a reply to message #24319]

Wed, 21 March 2001 19:47

Mark Hadfield
Messages: 783
Registered: May 1995

Senior Member

"Ted Graves" <egraves@socrates.Berkeley.EDU> wrote in message
news:99blck$ko7$1@agate.berkeley.edu...
> Hi all,
>
> Another lurker question ... let's say you define a pointer using the
PTR_NEW
> function and assign to a variable x. As long as you keep track of x and
don't
> reassign x and lose the pointer to the heap variable, things are great.
You
> can remove the heap variable from memory using the PTR_FREE procedure.
>
> But now let's say i have a function TEST that takes a pointer as an
argument,
> and i want to create a pointer on the fly to use in TEST. So i do
something
> like
>
> result = TEST(PTR_NEW(value))
>
> where value is whatever i want the heap variable to be. What happens to
the
> heap variable assigned in this statement after TEST returns? I'm assuming
> from that because of the way it was created, a heap variable now exists
that i
> can't easily get rid of without using HEAP_GC.

Yes.

But if you have access to the code of TEST you could do this:

pro test, a

; Do something with a

if not arg_present(a) then if ptr_valid(a) then ptr_free, a

end

---
Mark Hadfield
m.hadfield@niwa.cri.nz http://katipo.niwa.cri.nz/~hadfield
National Institute for Water and Atmospheric Research

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[Message index]

		Re: pointer question By: Martin Schultz on Mon, 26 March 2001 01:05
		Re: pointer question By: Mark Hadfield on Sun, 25 March 2001 14:16
		Re: pointer question By: Mark Hadfield on Sun, 25 March 2001 14:07
		Re: pointer question By: R.Bauer on Sun, 25 March 2001 09:24
		Re: pointer question By: Craig Markwardt on Thu, 22 March 2001 20:15
		Re: pointer question By: Paul van Delst on Thu, 22 March 2001 10:00
		Re: pointer question By: Pavel A. Romashkin on Thu, 22 March 2001 09:21
		Re: pointer question By: John-David T. Smith on Thu, 22 March 2001 08:56
		Re: pointer question By: Pavel A. Romashkin on Thu, 22 March 2001 08:24
		Re: pointer question By: Paul van Delst on Thu, 22 March 2001 06:52
		Re: pointer question By: Jaco van Gorkom on Thu, 22 March 2001 06:01
		Re: pointer question By: Mark Hadfield on Wed, 21 March 2001 19:47
		Re: pointer question By: Craig Markwardt on Mon, 26 March 2001 04:56
		Re: pointer question By: egraves on Mon, 26 March 2001 17:06

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