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From: johng@orstcs.UUCP
Newsgroups: comp.arch
Subject: Re: implementing shared libraries
Message-ID: <242800001@orstcs>
Date: Sat, 25-Apr-87 03:30:00 EDT
Article-I.D.: orstcs.242800001
Posted: Sat Apr 25 03:30:00 1987
Date-Received: Wed, 29-Apr-87 00:45:51 EDT
References: <12823@watnot.UUCP>
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Nf-ID: #R:watnot.UUCP:-1282300:orstcs:242800001:000:866
Nf-From: orstcs.cs.ORST.EDU!johng    Apr 25 01:30:00 1987


Apollo implements shared libraries.  Each new window you create you 'inlib'
the library you want.  Things are linked at program invokation.  I think
the linking of the AEGIS (operating system) calls are also postponed until
then also.  This allows for some neat tricks to be played.  You can overlay
your own routines over or around the operating system calls.  One example,
I wanted to catch and log all mouse movements before the application program
could munch on them, so I made my own version of the gpr_event_wait() which
looked like the real thing to the application program.  When it was called,
it called the real gpr_event_wait(), logged the transaction, and returned
the data.  I could do this without modifying the application's source, or
even recompiling since it was all done at invocation time.

				John Gregor
				{tektronix, hp-pcd}!orstcs!johng