Linking 3 process

-module(newbie).
-compile([export_all]).

starter() ->
  Pid = spawn(?MODULE, the_first_p, []),
  register(pidfirstp, Pid).

the_first_p() ->
  IsPidExists = whereis(pidsecondp),
  if IsPidExists =:= undefined ->
    Pid = spawn_link(?MODULE, the_second_p, []),
    register(pidsecondp, Pid);
    true -> true
  end,
  receive
    {From, "to first p", Msg} ->
      From ! {self(), "the_first_p()", Msg}
  end,
  the_first_p().

the_second_p() ->
  IsPidExists = whereis(pidthirdp),
  if IsPidExists =:= undefined ->
    Pid = spawn_link(?MODULE, the_third_p, []),
    register(pidthirdp, Pid);
    true -> true
  end,
  receive
    {From, "to second p", Msg} ->
      From ! {self(), "the_second_p()", Msg}
  end,
  the_second_p().

the_third_p() ->
  receive
    {From, "to third p", Msg} ->
      From ! {self(), "the_third_p()", Msg}
  end,
  the_third_p().

call_the_first() ->
  pidfirstp ! {self(), "to first p", "Halo first p!"},
  receive
    {Pid, FuncName, Msg} ->
      {Pid, FuncName, Msg}
  end.

call_the_second() ->
  pidsecondp ! {self(), "to second p", "Halo second p!"},
  receive
    {Pid, FuncName, Msg} ->
      {Pid, FuncName, Msg}
  end.

call_the_third() ->
  pidthirdp ! {self(), "to third p", "Halo third p!"},
  receive
    {Pid, FuncName, Msg} ->
      {Pid, FuncName, Msg}
  end.