You have a second problem, You shouldn't assign to $_ without localising it first, because it's often a reference to another variable. Better yet, localize *_.

local *_;

LOCK_LOOP:
    $_ = pop @left_to_lock;
    lock( $h{ $_ } );
goto LOCK_LOOP if @left_to_lock;

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In reply to Re: Looping without introducing a block by ikegami
in thread Looping without introducing a block by cmeyer

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