It seems like the guy analyzes how Pthreads are formally defined and declares that "Threads cannot be implemented as a library". Maybe if the title was changed to "Pthreads cannot be implemented as a library" it'd be true. Pthreads are fucking abysmal.
> We explicitly do not address the less frequently used environments in which multiple concurrent threads communicate communicate primarily through message passing, such as C programs communicating only through the MPI[34] library, or Erlang[11] or Concurrent ML[28] programs.
> We explicitly do not address the less frequently used environments in which multiple concurrent threads communicate communicate primarily through message passing, such as C programs communicating only through the MPI[34] library, or Erlang[11] or Concurrent ML[28] programs.
Heh, there's your answer. CSP FTW!