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From: guy@gorodish.UUCP
Newsgroups: comp.unix.wizards,comp.bugs.4bsd
Subject: Re: Addition to Arthur Olsen/4.3bsd table-driven ctime
Message-ID: <15918@sun.uucp>
Date: Tue, 31-Mar-87 06:03:02 EST
Article-I.D.: sun.15918
Posted: Tue Mar 31 06:03:02 1987
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Xref: utgpu comp.unix.wizards:1607 comp.bugs.4bsd:254

> Suppose I'm a software vendor (which I am, or at least I work for
> one), and I ship binary executables to my customers (which I do),
> executables which reference ctime and friends (which they do).
> What, if anything, should I do to ctime on my development system?
> I cannot be sure that my customers will install the necessary 
> timezone support files.

If you are a hardware vendor as well, you should just go ahead and
drop in the new timezone stuff and not worry about older systems,
unless you plan to build executables on a new whizzy system and have
them run on an old dingy system.  If you don't claim that software
built on version 5.0 of your OS will work on version 4.0 (and there
are very often excellent reasons *not* to claim this), no problem.
Presumably, installing version 5.0 of your OS also installs the
timezone support files (if it doesn't, somebody screwed up).

If you're just a software vendor, leave it alone.  Presumably, you'll
be building software on a BUBco Boring UNIX Box 1601, to sell to
people with BUBco Boring UNIX Boxes in the 1600 series.  If you build
it under version 5.0 under BUBIX, and only claim that it runs under
5.0 or later versions, you can assume that the time zone support
files are already there.  If you build it under 4.0, and BUBco claims
that programs built under 4.0 will still run under 5.0, as long as
you trust BUBco you can assume that there's no problem.

The only problem occurs if you build things under 5.0 expecting them
to work under 4.0.  If BUBco claims that this is the case, then
either they're lying or they've already set "ctime" up properly.  If
they don't claim that this is the case, then you shouldn't be
assuming that it *is* the case.

(If you're monkeying with BUBco's "libc.a", then you'd better *know*
what you're doing, and be prepared for unpleasant surprises anyway.
Think carefully before you overwrite your vendor's "ctime" code, if
you're planning to use that machine to develop software to be
installed on other machines that may not have installed the new
"ctime" stuff.)

*BUB and Boring UNIX Box are Trademarks of Russell Sandberg Enterprises.