
  [;1m-spec link(PidOrPort) -> true when PidOrPort :: pid() | port().[0m

  Sets up and activates a link between the calling process and
  another process or a port identified by [;;4mPidOrPort[0m. We will from
  here on call the identified process or port linkee. If the linkee
  is a port, it must reside on the same node as the caller.

  If one of the participants of a link terminates, it will send an
  exit signal to the other participant. The exit signal will
  contain the exit reason of the terminated participant. Other
  cases when exit signals are triggered due to a link are when no
  linkee exist ([;;4mnoproc[0m exit reason) and when the connection
  between linked processes on different nodes is lost or cannot be
  established ([;;4mnoconnection[0m exit reason).

  An existing link can be removed by calling [;;4munlink/1[0m. For more
  information on links and exit signals due to links, see the 
  Processes chapter in the Erlang Reference Manual:

   • Links

   • Sending Exit Signals

   • Receiving Exit Signals

  For historical reasons, [;;4mlink/1[0m has a strange semi-synchronous
  behavior when it is "cheap" to check if the linkee exists or not,
  and the caller does not trap exits. If the above is true and the
  linkee does not exist, [;;4mlink/1[0m will raise a [;;4mnoproc[0m error 
  exception. The expected behavior would instead have been that [;;4m[0m
  [;;4mlink/1[0m returned [;;4mtrue[0m, and the caller later was sent an exit
  signal with [;;4mnoproc[0m exit reason, but this is unfortunately not
  the case. The [;;4mnoproc[0m exception is not to be confused with an 
  exit signal with exit reason [;;4mnoproc[0m. Currently it is "cheap" to
  check if the linkee exists when it is supposed to reside on the
  same node as the calling process.

  The link setup and activation is performed asynchronously. If the
  link already exists, or if the caller attempts to create a link to
  itself, nothing is done. A detailed description of the link
  protocol can be found in the Distribution Protocol chapter of
  the ERTS User's Guide.

  Failure:

   • [;;4mbadarg[0m if [;;4mPidOrPort[0m does not identify a process or a node
     local port.

   • [;;4mnoproc[0m linkee does not exist and it is "cheap" to check if
     it exists as described above.
