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From: tale@pawl.rpi.edu (David C Lawrence)
Newsgroups: news.software.b,comp.sources.d
Subject: Re: C News "upact" in Perl 3.0
Message-ID: <empty.stack.4D9D@rpi.edu>
Date: 22 Nov 89 06:17:13 GMT
References: <2565B57C.10978@ateng.com> <1989Nov19.014731.26346@utzoo.uucp>
	<25682EB0.24425@ateng.com>
Organization: Rensselaer Polytechnic Institute, Troy NY
Lines: 43

According to henry@utzoo.uucp (Henry Spencer):
Henry> Uh, in any modern C News distribution you will find
Henry> updatemin.c, which does the same thing in C.

In <25682EB0.24425@ateng.com> chip@ateng.com (Chip Salzenberg) writes:
Chip> Uh...  I knew that.   :-)

I didn't know it.  I'm glad your posting prompted Henry's note, for
two reasons.

A) It munged my active file by always setting $min to 1 + $max.
B) updatemin is faster anyway.  It fixed the damage done by the perl
upact pretty quickly. :-)

Now I am also quite content to run updatemin nightly from cron after
expire.

The problem with upact was in dirlow().  $min never got set.  I don't
understand exactly what was failing, but many printf's later I tracked
it down to the fact that though $low was being set in the "while"
control structure, it's value was still "" when it exited:

sub dirlow {
        local ($dir) = @_;
        local ($low, $f);

        opendir(dir,$dir) || return "";
        $low = "";
        while ($f = readdir(dir)) {
                printf "%s\n", $f;
                next unless $f =~ /^[0-9]+$/;
                $low = $f if ($low eq "") || ($f < $low);
        }
        closedir(dir);
        return $low;
}

This is in perl 3.0.1.2, patchlevel 6, GCC 1.35 compiled on a Sun 3,
SunOS 4.0.3 system.

Dave
-- 
 (setq mail '("tale@pawl.rpi.edu" "tale@ai.mit.edu" "tale@rpitsmts.bitnet"))