comp.lang.idl-pvwave archive: archive

Home » Public Forums » archive » Re: Help: Pointer

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: Help: Pointer [message #14865]

Sat, 03 April 1999 00:00

steinhh
Messages: 260
Registered: June 1994

Senior Member

Vu Khac Tri wrote:

> But in C, when c is modified, (*pc) is also modified because
> pc points to the memory where c is. That mean, if c = 5, *pc = 5.

You're right. IDL doesn't have pointers in the same sense
as C does - there is no "address of" operator, and there
is no way to make a pointer that points to a normal variable.

The closest thing (and it's close enough to emulate
the C behaviour, but not it's notation) is:

IDL> c=ptr_new(4)
IDL> pc=c
IDL> print,*pc
4
IDL> *c = 5
IDL> print,*pc
5

I.e., you have two pointers, pointing to the same heap
variable. The only difference from C notation is that
you have to dereference *both* variables as pointers.

Regards,

Stein Vidar

Report message to a moderator

[Message index]

		Re: Help: Pointer By: steinhh on Sat, 03 April 1999 00:00
		Re: Help: Pointer By: VU KHAC Tri on Fri, 02 April 1999 00:00
		Re: Help: Pointer By: davidf on Fri, 02 April 1999 00:00

Previous Topic:	"ALOG2" ? (Ugly code follows)
Next Topic:	"ALOG2" ?

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 15 08:04:55 PDT 2025

Total time taken to generate the page: 0.08013 seconds