Process created by spawn_link/1 do not exit as we expected

[Pengfei Wang]

Hi all: 
    
Error ====>:~p~n was printed many times, why?



real log:

14:07:40.000 [info] ====>
cmpp_sms_sp_30:1123 Error sms_sp_receiver receive head error,close connection ====> 
 self:"<0.27996.1553>" Error:{error,closed}

14:07:40.000 [info] ====>
cmpp_sms_sp_30:1123 Error sms_sp_receiver receive head error,close connection ====> 
 self:"<0.27996.1553>" Error:{error,closed}

14:07:40.000 [info] ====>
cmpp_sms_sp_30:1123 Error sms_sp_receiver receive head error,close connection ====> 
 self:"<0.27996.1553>" Error:{error,closed}

14:07:40.000 [info] ====>
cmpp_sms_sp_30:1123 Error sms_sp_receiver receive head error,close connection ====> 
 self:"<0.27996.1553>" Error:{error,closed}

14:07:40.000 [info] ====>
cmpp_sms_sp_30:1123 Error sms_sp_receiver receive head error,close connection ====> 
 self:"<0.27996.1553>" Error:{error,closed}

14:07:40.000 [info] ====>
cmpp_sms_sp_30:1123 Error sms_sp_receiver receive head error,close connection ====> 
 self:"<0.27996.1553>" Error:{error,closed}

14:07:40.000 [info] ====>
cmpp_sms_sp_30:1123 Error sms_sp_receiver receive head error,close connection ====> 
 self:"<0.27996.1553>" Error:{error,closed}

14:07:40.001 [info] ====>
cmpp_sms_sp_30:509 Error exit_receiver ====> 
 spcode:"230166"
 splinkid:"1"
 ip:"123.207.73.149"
 max:1000
 Receiver:<0.27996.1553>

example code:

parent()->
    {ok, Socket} = gen_tcp:connect/4,
    start_receiver(999, self(), Socket),
    gen_tcp:send/2,
    gen_tcp:close(Socket).

start_receiver(SpCode, Sender, Socket) ->
    spawn_link(fun() -> receiver(SpCode, Sender, Socket) end).

receiver(SpCode, Sender, Socket) -> 
    case gen_tcp:recv(Socket, 12) of
        {ok, Head} ->
            case Head of
                <<_Rep_Toltal_len:32/integer, Rep_Command_id:32/integer, _Rep_Seq_id:32/integer>> ->

                    CommandId = erlang:integer_to_list(Rep_Command_id, 16),
                    
                    case CommandId of
                        A -> 
                            receiver(SpCode, Sender, Socket); 
                        UnknownCmd ->
                            receiver(SpCode, Sender, Socket)
                    end;
                _ErrorHead ->
                    gen_tcp:close(Socket)
             end;
        Error ->
            gen_tcp:close(Socket),
           error_logger:info_msg(" Error sms_sp_receiver receive head error,close connection~n self:~p Error:~p~n ",[Error])           
    end.

[Pengfei Wang]

my english is not very well, can you understand my idea?

在 2017年9月28日星期四 UTC+8下午3:08:42，Pengfei Wang写道：