First off, i'd highly suggest using flock() if at all possible.

The big limitation here is that File::lockf is a Perl binding to the SYSV lockf(3) call. Since lockf(3) will never return a 9, my guess is that the Perl binding (File::lockf) is returning the value that errno is set to.

Now the next hurdle; how do you figure out what an errno value corresponds to? ... with the strerror(3) (POSIX/SYSV/BSD/ISO 9899, etc) call. OOOoooh loook, it conforms to POSIX! =) That means that we're in luck (*this* time), since Perl has a fairly complete POSIX module.

The short answer (this is barebones, no strict or anything... and *just* a snippet): 
use POSIX;
use File::lockf;
$status = File::lockf::lock ($args); # replace $args as appropriate.

if ($status) {
   # Uh oh, non zero value returned.
   # Lets use POSIX's errstr() to find out what happened
   $error_string = strerror ($status);
   die "Uh oh, lockf returned '$error_string'";
}

[download]

The real answer: flock

=)

Update: I forgot to mention, in this case, with a status of '9', the error is "Bad file descriptor". This means that something was wrong with your filehandle.

In reply to Re: File::lockf and the lock() return value by count0
in thread File::lockf and the lock() return value by SLG150

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