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From: elg@usl.UUCP
Newsgroups: comp.arch,comp.unix.wizards,comp.os.misc
Subject: Re: Shared libraries (Was: Re: Big Programs Hurt Performance)
Message-ID: <266@usl>
Date: Tue, 29-Sep-87 11:48:56 EDT
Article-I.D.: usl.266
Posted: Tue Sep 29 11:48:56 1987
Date-Received: Sun, 4-Oct-87 02:18:53 EDT
References: <28957@sun.uucp>
Organization: CACS, Univ of SW La, Lafayette, LA
Lines: 28
Xref: utgpu comp.arch:2320 comp.unix.wizards:4312 comp.os.misc:245

in article <28957@sun.uucp>, guy%gorodish@Sun.COM (Guy Harris) says:
>> >It's not too uncommon that a new version of a program comes along, but some
>> >people still want to use the old version, for whatever reason.  
>> You have to relink with the unshared version of the old library.
> You do in some, but not all, implementations.  An earlier article indicated
> that the Amiga implementation permits you to specify a version number when the
> library is opened (does this mean programs have to explicitly open shared
> libraries, i.e., they have to know that they're using a shared library?).

The Amiga operating system consists of a tiny multi-tasking
message-passing kernel, various system processes to handle I/O, the
mouse, etc., and a whole slew of libraries, all of which are shared,
all of which are loaded upon demand (i.e. 'opened'). So yes, programs
have to explicitly open shared libraries. However, Amiga "C" compilers
handle that for stdio and other "vanilla" stuff, it's just when you're
worrying about windowing and other down'n'dirty machine-dependent
stuff that you need to explicitly worry about opening and closing
libraries.

Needless to say, the Amiga OS is not Unix, for one thing, Unix isn't
going to run on a 512K machine with no MMU and two floppies. So they
don't have to worry about backward compatibility with Version 7 &
earlier programs written 15 years ago like Sun does :-).

--
Eric Green  elg@usl.CSNET       from BEYOND nowhere:
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{akgua,killer}!usl!elg        "there's someone in my head, but it's not me..."