tye, Thanks for the input. I tried your suggestion, and when configured as you suggest, the flock dies with the message "Resource temporarily unavailable". Wow. What does that mean? I mean, it says what it says, yeah. But what does it really mean, in terms of flocking? It's quite strange. When I made a temp directory of my own "/home/username/htdocs/tmp" and made it chmod 777, it was able to flock just fine.
So is there an issue with flocking files which are not in your own userspace (i.e. /tmp or something), perhaps?

Update: Incidentally, I got this very same result with the script on two different machines: one running Slack 7, and the other running FreeBSD 3.1
Update 2: I just had to try the simplest version, so I did this: 
#!/usr/bin/perl

use Fcntl qw( :flock );

my $tempfile="/tmp/$$.temp";
print "Content-type: text/html\n\n";
print "Testing flocking now.<BR>\n";

open(TMP, "+> $tempfile") or die "Could not open tempfile: $!";
flock(TMP, LOCK_EX|LOCK_NB) or die "no lock: $!";
seek(TMP, 0, 0);
print TMP "Blah blah blah"; # just to test
close(TMP);
unlink $tempfile;

print "That seemed to go just fine.\n";

[download]
And it ran just fine. Go figure. I'm quite puzzled.

In reply to (Kozz) Re: More Eyes by Kozz
in thread More Eyes, Please by Kozz

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.