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Re: Calling data from a structure of pointers? [message #43020]

Fri, 11 March 2005 09:16

Jonathan Greenberg
Messages: 91
Registered: November 2002

Member

Hi all -- looks like I had been doing this is a bit wrong -- it did end up
working right -- *structure.pointer[x] was what I needed (I didn't include
the [] it turns out)...

--j

On 3/10/05 10:57 PM, in article d0rfgv$d6v$1@defalla.upc.es, "Antonio
Santiago" <d6522117@est.fib.upc.es> wrote:

> Jonathan Greenberg wrote:
>
>> How do I retrieve the data the pointers are referring to?
>
> pStr is pointer to a structure variable. This strucutre has 2 pointer
> fields.
>
> pStr = PTR_NEW(
> {
> a: PTR_NEW(10),
> b: PTR_NEW(INDGEN(3))
> })
>
>
> pStr - Pointer variable to structure stored in HEAP memory.
> IDL> help, pStr
> PSTR POINTER = <PtrHeapVar6>
>
> *pStr - The content that pStr points to, that is, the structure
> stored in HEAP memory.l
> IDL> help, *pStr, /STRUCT
> ** Structure <1f06f8>, 2 tags, length=8, data length=8, refs=1:
> A POINTER <PtrHeapVar4>
> B POINTER <PtrHeapVar5>
>
> (*pStr).a - First "get" the strucutre and then access to the firts
> pointer field 'a'.
> IDL> help, (*pStr).a
> <Expression> POINTER = <PtrHeapVar4>
>
> (*(*pStr).a) - The same as above but obtain the content that 'a'
> points (10).
> IDL> help, (*(*pStr).a)
> <PtrHeapVar4> INT = 10
>
> And the same for 'b' field:
> IDL> help, (*pStr).b
> <Expression> POINTER = <PtrHeapVar5>
> IDL> help, (*(*pStr).b)
> <PtrHeapVar5> INT = Array[3]
>
>
> IDL> arr = *(*pStr).b
> IDL> print, arr
> 0 1 2
>
>
>

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[Message index]

		Re: Calling data from a structure of pointers? By: Jonathan Greenberg on Fri, 11 March 2005 09:16
		Re: Calling data from a structure of pointers? By: Antonio Santiago on Thu, 10 March 2005 22:57
		Re: Calling data from a structure of pointers? By: R.G.Stockwell on Thu, 10 March 2005 15:09
		Re: Calling data from a structure of pointers? By: David Fanning on Thu, 10 March 2005 14:46

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