Re: pointer question

["Mark Hadfield" <m.hadfield(at)niwa.cri.nz>]

"Ted Graves" <egraves@socrates.Berkeley.EDU> wrote in message
99blck$ko7$1@agate.berkeley.edu">news:99blck$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