Re: Call back, was Re: Adding pointers to RPG language.

["Joep Beckeringh" <joep@xxxxxxxxxxxxxxxxxxx>]

Rob,

One of the things that was mentioned was qsort.  This is a C-library
function that sorts a list of elements.  But to sort elements, qsort has to
have a way to compare two elements (these elements might be structures that
you want sorted on the fourth element).  So you have to write a function
that receives (pointers to) two elements and returns (IIRC) -1, 0 or 1 for
'a < b', 'a = b' and 'a > b'.  When you call qsort, you pass (a pointer to)
this function; every time qsort needs to compare two elements, it 'calls
back' your function.

Joep Beckeringh

----- Original Message -----
From: <rob@dekko.com>
To: <rpg400-l@midrange.com>
Sent: Tuesday, January 15, 2002 5:45 PM
Subject: Call back, was Re: Adding pointers to RPG language.


>
> Ok, now you've got my interest.  What's a callback?
>
> Rob Berendt