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From: pl@kaarne.tut.fi (Pertti Lehtinen)
Newsgroups: comp.sys.amiga.tech
Subject: SetFunction (was Re: Patching dos-library)
Message-ID: <6637@etana.tut.fi>
Date: 3 Apr 89 09:17:36 GMT
Sender: News@tut.fi
Reply-To: pl@kaarne.tut.fi (Pertti Lehtinen)
Organization: Tampere University of Technology, Finland
Lines: 27

From article <6462@cbmvax.UUCP>, by eric@cbmvax.UUCP (Eric Cotton):
> 
> SetFunction does indeed return a pointer to the old function.
> 
> 	oldFunc = SetFunction(library, funcOffset, funcEntry)

	That makes things interesting.

	How does find out the address of original function?

	Does it copy old stub somewhere and return address to that?

	Or does it simply use stub as normal library stub (jmp xxx),
	and return xxx.  In this case it isn't surprising that
	it doesn't work with DOS-library.

	Exec manual don't say anything about return value,
	so does it just happen
	under certain circumstances or is it on purpose?

					Pertti Lehtinen
					pl@tut.fi

pl@tut.fi				! -------------------------------- !
Pertti Lehtinen				!  Alone at the edge of the world  !
Tampere University of Technology	! -------------------------------- !
Software Systems Laboratory