I'm surprised no one has pointed you to sysopen(), rather than the simpler open() function.

From the perlopentut tutorial:

To get an exclusive lock, typically used for writing, you have to be careful. We sysopen the file so it can be locked before it gets emptied. You can get a nonblocking version using LOCK_EX | LOCK_NB. 
    use 5.004; # make sure you have at least this level perl
    use Fcntl qw(:DEFAULT :flock);
    sysopen(FH, "filename", O_WRONLY | O_CREAT)
        or die "can't open filename: $!";
    flock(FH, LOCK_EX)
        or die "can't lock filename: $!";
    truncate(FH, 0)
        or die "can't truncate filename: $!";
    # now write to FH

[download]

[Jon]

In reply to Re: Order of flock and open by theguvnor
in thread Order of flock and open by svsingh

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