Path: utzoo!utgpu!water!watmath!clyde!ima!johnl
From: johnl@ima.ima.isc.com (John R. Levine)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Overlays & Function Pointers
Message-ID: <2735@ima.ima.isc.com>
Date: 4 Oct 88 22:57:29 GMT
References: <542@optilink.UUCP>
Reply-To: johnl@ima.UUCP (John R. Levine)
Organization: Not much
Lines: 15

In article <542@optilink.UUCP> cramer@optilink.UUCP (Clayton Cramer) writes:
>Consider this a warning.
>
>[the MS overlay manager fails when you call functions indirectly because
> it works by fudging the call instruction]

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
{ bbn | think | decvax | harvard | yale }!ima!johnl, Levine@YALE.something
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