Re: Basing Pointers

[Pete Hall <pbhall@xxxxxxxxxx>]

At 07:06 05/19/1999 , Leif wrote:
>could someone define for me what 'basing pointers' might mean then?

A pointer is a variable that contains a memory address. A based variable or
structure is one whose address is determined by the pointer. This pointer
can then be referred to as a basing pointer. What's it good for? You can
have a data space, which is simply a contiguous sequence of bytes. You can
also have a based data structure that describes the data in the space. If
you set the basing pointer to the address of the first byte of the data
space (or to an offset within the space), the contents of the space can be
retrieved by referencing the data structure subfields. This is frequently
done when manipulating data returned by APIs, but it is also useful in
simulating multi-dimensional arrays, and the RPG equivalent of the COBOL
OCCURS construct.


Pete Hall
pbhall@execpc.com
http://www.execpc.com/~pbhall
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