Hi,
you can use flock in this way
#!/usr/bin/perl -w
use strict;
use Fcntl ':flock'; # import LOCK_* constants

sub lock {
    flock(FH,LOCK_EX);
    # and, in case someone appended
    # while we were waiting...
    seek(FH, 0, 2);
}

sub unlock {
    flock(FH,LOCK_UN);
}

my $filename = "plain-db.pdb";

open(FH, ">>$filename")
    or die "Can't open file ($filename): $!";

lock();

# do what ever you want with it 

unlock();

[download]
Maybe this can help you.

In reply to Re: How to apply flock by Chief of Chaos
in thread How to apply flock by kiat

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.