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From: bzs@bu-cs.BU.EDU (Barry Shein)
Newsgroups: net.unix-wizards,net.unix
Subject: ld and the -A option
Message-ID: <2223@bu-cs.bu-cs.BU.EDU>
Date: Sun, 2-Nov-86 23:22:31 EST
Article-I.D.: bu-cs.2223
Posted: Sun Nov  2 23:22:31 1986
Date-Received: Tue, 4-Nov-86 00:22:04 EST
Organization: Boston U. Comp. Sci.
Lines: 17
Xref: mnetor net.unix-wizards:8576 net.unix:6121


>Can anyone explain exactly how this feature may be used ?  The man page
>indicates that it may be used to generate an a.out file that may be
>read into an already executing program (eg like an overlay or dynamic
>loading ???).  It is not clear how this can be done.

Yes, you (and the man page) are correct, for example Franz Lisp uses
the -A flag to relocate compiled lisp modules for loading. Similarly
I once wrote a dynamic link loader which used -A similarly.
(sorry, it was under contract, I don't own it.)

The basic idea is that you figure out where the code will want to be
loaded and build and run an 'ld -A xyzzy' command to re-locate it, the
rest is fairly straightforward (after staring at things for a while.)
You may want to have a look at the -T option also.

	-Barry Shein, Boston University