Path: utzoo!attcan!uunet!husc6!bloom-beacon!apple!voder!kontron!optilink!cramer
From: cramer@optilink.UUCP (Clayton Cramer)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Overlays & Function Pointers
Message-ID: <545@optilink.UUCP>
Date: 5 Oct 88 17:40:56 GMT
References: <542@optilink.UUCP> <2735@ima.ima.isc.com>
Organization: Optilink Corporation, Petaluma, CA
Lines: 20

In article <2735@ima.ima.isc.com>, johnl@ima.ima.isc.com (John R. Levine) writes:
> In article <542@optilink.UUCP> cramer@optilink.UUCP (Clayton Cramer) writes:
> Phoenix's PLINK linker has an overlay manager that works just fine when
> you call functions indirectly.  Rather than fooling with the code at the
> call point, it replaces references to a function's address by references
> to a thunk that makes sure the overlay is loaded, then jumps to the actual
> code.  Since the thunk has a real address, you can call it any way you want.
> -- 
> John R. Levine, IECC, PO Box 349, Cambridge MA 02238-0349, +1 617 492 3869

Very true, and I know that it works because we used PLINK on my last
project, and we used indirect function calls and never had to confront
this problem.  But there is a price -- doesn't every function end up
having a stub in the root, whether it is overlaid or not?



-- 
Clayton E. Cramer
..!ames!pyramid!kontron!optilin!cramer