RE: RPG IV Pointers

[Joel Fritz <JFritz@xxxxxxxxxxxxxxxx>]

Minor semantic point--A null pointer is a pointer that contains a system
dependent predefined address value that's convenient to think of as 0.  The
pointer that's not typecast or typed in C/C++ is called a "void" pointer,
which actually is a data type.

RPG initializes all pointers to *NULL when you declare them, just like it
initializes numerics to 0 and character strings to *BLANKS.

I've had too much coffee this morning, they should have cut me off sooner.
<g>

-------------------------------------------
A mind is a terrible thing to use.

Joel Fritz 


> -----Original Message-----
> From: Jim Langston [mailto:jlangston@conexfreight.com]
> Sent: Wednesday, March 01, 2000 8:33 AM
> 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
> 
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