If this were my code, I would probably not write it this way to begin with. Instead, I would assign the reference returned by IO::File->new to a scalar then check to make sure it's defined.

Something like:

my $fh = IO::File->new($file, O_WRONLY|O_CREAT|O_EXCL,0644);
die "Can't create $file: $!\n" unless defined $fh;
return $fh;
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Instead of:

return IO::File->new($file, O_WRONLY|O_CREAT|O_EXCL,0644)
        or die "Can't create $file: $!\n";
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