First: what is the error message you are getting when the flock fails?

Second: how are you defining LOCK_EX? Is it possible that you are defining that locally somewhere and its value is not being passed to the function?

Third: Check all return calls! 

$filelog = "file.log";
open  FILE, $filelog    or die "Can't open $filelog: $!\n";
flock FILE, LOCK_EX     or die "Can't write-lock $filelog: $!\n";
print FILE "$a:$b:$c\n" or die "Can't print to $filelog: $!\n";
close FILE              or die "Can't print to $filelog: $!\n";

[download]
The $! variable will have the error code that was generated by the failure. This may give you more information. However, if you don't have the or die construct in there, you may have a failure prior to your failure to flock the file.

Also, notice that file.log is replaced by a variable rather than hardcoded. If you need to change this value in the future, you'll hate yourself for not doing this :)

And yes, closing a file dissolves the flock.

Cheers,
Ovid

In reply to Re: flock problem by Ovid
in thread flock problem by Anonymous Monk

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.