Re: SORTA of a qualified data structure

[Barbara Morris <bmorris@xxxxxxxxxx>]

Vern Hamberg wrote:
> 1. Dimension the data structure - give it a length equal to the sum of 
> the lengths of those 7 fields.

Right, except you don't need to explicitly specify the length of a 
qualified data structure.  Better to let the compiler figure out the 
length unless you really need the data structure to have a particular 
length longer than the natural subfields would give it.

> 2. Take the dim() off each subfield

Right.

> 3. Use OVERLAY on each subfield, overlaying the DS itself, with the 
> first subfield overlaying at position 1 and all the remaining ones using 
> *NEXT

Or just code the subfields without the overlay keywords.  Using 
OVERLAY(DS:*NEXT) wouldn't add anything.

> Now when you do the sort you describe, do it just as you have it - the 
> subfields end up being arrays, would you believe, and sorting one takes 
> all the rest with it.

You can't sort the data structure array by specifying one of the 
subfields even if the subfields are defined to overlay the DS.

This is illegal if ArSf1 is an array:
    SORTA ArSf1.ArField4

But in 7.1, you can code this to sort the ArSf1 data structure array by 
the ArField4 subfield, keeping the other subfields in synch the way 
Booth wants:
    SORTA ArSf1(*).ArField4

Prior to 7.1, you have to jump through a few hoops to sort the DS array 
by one of its subfields.  Paul's article mentions one way using 
pointers, but that way seems quite error prone to me.  I'd use qsort 
instead no matter how big the array is; qsort is quite straightforward 
once you'd done it once.