Creating and using a Lockfile 1

[netman4u]

Hello all,

I am trying to create a lockfile in my program to ensure only one instance is running at a time. I'm having some troubles getting my logic working. Here is my code:

#!c:\\perl\\bin\\perl 
use strict;
use warnings;
my $lock_file = "D:\\Stage\\lockfile";
if (-e $lock_file) {
	print "Found lock file $lock_file.
        exit 1;
}
open (LOCK, "+>$lock_file")or die ("Error opening $lock_file $1");;
print LOCK "print some junk\n";
close LOCK;
print "$lock_file\n";
if (unlink($lock_file) == 0) {
    print "File deleted successfully.";
} else {
    print "File was not deleted.";
}

The output I get EVRYTIME I run the program is:

D:\Stage\lockfile
File was not deleted.

It seems so simple I want to create the lockfile and if the program completes ok I want to delete it. But the file is never created and so never deleted!

If at first you don't succeed, don't try skydiving.

 

[KevinADC]

zero means the function failed, try using one to test for success:

if (unlink($lock_file) == [b]1[/b]) {
    print "File deleted successfully.";
} else {
    print "File was not deleted.";
}

 

[netman4u]

Haaa! So it was being created and deleted it just happened so fast I could not see it! Thanks Kevin.

I got that right of a web tutorial to!

http://www.tizag.com/perlT/perldelete.php

Whats the world comming to when you can't trust what you see on the web!

If at first you don't succeed, don't try skydiving.