controlling_process can return {error, badarg}

For gen_tcp, gen_udp and gen_sctp controlling_process/2 can return
badarg if erlang:port_connect/2 fails with badarg. This can easily
happen if the new owner is not alive but in some race condition also
when the socket is closed right before port_connect/2 (and after the
previous socket function)
This commit documents this behaviour.

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/kernel/doc/src/gen_tcp.xml b/lib/kernel/doc/src/gen_tcp.xml
index 08454b9832..e97db20062 100644
--- a/lib/kernel/doc/src/gen_tcp.xml
+++ b/lib/kernel/doc/src/gen_tcp.xml
@@ -231,7 +231,11 @@ do_recv(Sock, Bs) ->
           <c><anno>Socket</anno></c>. The controlling process is the process
           that receives messages from the socket. If called by any other
           process than the current controlling process,
-          <c>{error, not_owner}</c> is returned.</p>
+          <c>{error, not_owner}</c> is returned. If the process identified
+          by <c><anno>Pid</anno></c> is not an existing local pid,
+          <c>{error, badarg}</c> is returned. <c>{error, badarg}</c> may also
+          be returned in some cases when <c><anno>Socket</anno></c> is closed
+          during the execution of this function.</p>
           <p>If the socket is set in active mode, this function
           will transfer any messages in the mailbox of the caller
           to the new controlling process.