c:>perl -de 1

Loading DB routines from perl5db.pl version 1.23
Editor support available.

Enter h or `h h' for help, or `perldoc perldebug' for more help.

main::(-e:1):   1
  DB<1> use Devel::Peek;

  DB<2> $a = undef;

  DB<3> Dump $a;
SV = NULL(0x0) at 0x1aecc18
  REFCNT = 1
  FLAGS = ()

  DB<4> $b = \$a;

  DB<5> Dump $a;
SV = NULL(0x0) at 0x1aecc18
  REFCNT = 2        ###<--------correct here
  FLAGS = ()