You mean this?

# This is a trick used to prevent concurrent applications
# from running, but that will work WITHOUT needing pid
# or lock files, and so is kill -9 or power failure safe.
# To work it needs a __DATA__ section to be defined at
# the end of the file.
use Fcntl 'LOCK_EX', 'LOCK_NB';
unless ( flock DATA, LOCK_EX | LOCK_NB ) {
    # An existing instance of this application is already running
    print STDERR "Program is already running\n";
    exit(0);
}

__DATA__
Used as a lock to prevent concurrent execution.
Do not remove this data section.

[download]


Of course, I'm not sure how well it would work on Win32, but I'm sure there's an equivalent

In reply to Re^3: Windows process by adamk
in thread Windows process by qadwjoh

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.