in reply to Re: Flocking and In-place editing
in thread Flocking and In-place editing

Thanks to Mark for the quick reply. Would you then flock the file like this? 
use Fcntl ':flock';

@ARGV = "file.tab";
$^I = ".bak";

flock(ARGV,LOCK_EX);
seek(ARGV, 0, 2);

while (<>) {

s/foo/bar/;

print;
}

flock(ARGV,LOCK_UN);

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Does anybody know if this is right, or even the way to lock whilst using inplace editing? Regards, Phil

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Re: Re: Re: Flocking and In-place editing
by Anonymous Monk on Jan 27, 2004 at 18:00 UTC
    Always error check your syscalls. It's easy to do. If you had written this: 
    flock(ARGV,LOCK_EX) or die "flock failed: $!";

    [download]
    You would have seen an error message like this: 
    flock failed: Bad file descriptor at foo line 6.

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    The problem is that the ARGV filehandle isn't open util you hit the while (<>) { line, so you can't lock it. After that, it's too late to lock. Follow one of the other suggestions, and either lock a separate lockfile, or write your own in-place edit code. The built-in $^I is nice for a quick script, but it's not always the best way to go.
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