$ perl -Mthreads -MDevel::Peek -e"my $locked=1; my $unlocked=1; Dump($unlocked); lock($locked); Dump($locked)"

SV = IV(0x98a490) at 0x98a494
  REFCNT = 1
  FLAGS = (PADMY,IOK,pIOK)
  IV = 1
SV = IV(0x3e8c10) at 0x3e8c14
  REFCNT = 1
  FLAGS = (PADMY,IOK,pIOK)
  IV = 1