#!/usr/bin/perl -w


use Fcntl qw(LOCK_EX);


# instrument LOCK_EX


my $lock_ex_coderef = \&Fcntl::LOCK_EX;





my $newglob = *Fcntl::LOCK_EX = sub {


    print "LOCK_EX called\n";


    no warnings 'redefine';


    *Fcntl::LOCK_EX = $lock_ex_coderef;


    if (wantarray) {


	my @ret = &$lock_ex_coderef;


	*Fcntl::LOCK_EX = $newglob;


	@ret;


    } else {


	my $ret = &$lock_ex_coderef;


	*Fcntl::LOCK_EX = $newglob;


	$ret;


    }


};





# call LOCK_EX


print $_ = LOCK_EX;


print "\n";