IIRC Windows locks the file when opened. You may be able to check the file lock state, maybe something like this (I have no windows box to test): 
open my $fh, "/some/file" or die "can't open!";

# try/catch file locking
eval { flock $fh, 'LOCK_EX' or die "can't lock!" };
if ( $@) {
    warn "open file!" && exit;
}

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In reply to Re: Check whether the file is in use by an other user by wazoox
in thread Using Win32::OLE and Excel - Tips and Tricks by cacharbe

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