Re: RPG IV Pointers

[Jim Langston <jlangston@xxxxxxxxxxxxxxxx>]

Not two pointers, per se, but a pointer and a pointer referancer.

Regards,

Jim Langston

Colin Williams wrote:

> Why do you think you need two pointers in RPG?
>
> -----Original Message-----
> From: Jim Langston [mailto:jlangston@conexfreight.com]
> Sent: Wednesday, March 01, 2000 4:33 PM
> To: RPG400-L@midrange.com
> Subject: Re: RPG IV Pointers
>
> Actually, a null pointer is a pointer that is not "cast".  In C you
> "cast" the type of data that the pointer is going to point to.  So,
> you can set up a pointer to point to type Char, or type Int, or
> whatever, then you can just look at the data by "dereferancing"
> the pointer directly.
>
> In RPG, however, all pointers seem to be null pointers (not cast)
> so to look at the data you actually do it through a different type
> of cast pointer, in our example, MyField.
>
> The way it works in RPG does not go 1 on 1 with C, two different
> ways of doing things.  In C, it only requires 1 pointer to do what you
> need 2 pointers to do in RPG.  Not necessarily bad, mind you, but
> different, and something I just had to understand to be able to use it.
>
> Regards,
>
> Jim Langston
>
> Colin Williams wrote:
>
> > Personally, I like to think of it as a data structure with a pointer
> > attached to it, that I can set to any value.
> >
> > Got some data in a user space, set the pointer to the start
> of the user
> > space, and look at the data via the data structure
> > Got some data in another data structure, set the pointer to
> the start of
> > the other data structure, and look at the other data structure via the
> > data structure
> >
> > Is a null pointer any pointer that has not been set yet?

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