[Quickfix-users] What is correct behavior if sender has error sending msg?

[Brendan B. B. <br...@ka...>]

Hello,

In bool Session::sendRaw( Message& message, int num ) it calls

--> Session::fill( Header& header ) which calls
    --> header.setField( MsgSeqNum( getExpectedSenderNum() ) );

to set the Sender's MsgSeqNum of this msg to be sent to the target.

Then calling

--> std::string& Message::toString( std::string& str ) const which calls
    --> bool Session::send( const std::string string ) which calls
        --> bool SocketConnection::send( const std::string& msg ) which
calls
            --> bool socket_send( int s, const char* msg, int length )

which Returns true for no error, false otherwise.

Percolating back up to Session::sendRaw(), this results in
   result = send( message.toString(messageString) );
result being false if an error occured sending the message.

There's no check however in Session::sendRaw() if there was an error
so the SenderMsgSeqNum remains incremented yet this message is not
logged to the store.  When a connection is reestablished the target
will issue Resend requests for the Msgs w/MsgSeqNum which weren't
sent.  Since they weren't sent (and thus weren't logged) those
request aren't honored.

I haven't debugged further to see if the Sender should be generating
a Sequence Reset in this case (should it?) but would an acceptable
response be to reset the Sender MsgSeqNum back to the value prior to
the failed call e.g. in Session::sendRaw():

bool Session::sendRaw( Message& message, int num )
{
   ...
   result = send( message.toString(messageString) );

    // brendan, 7/11: If socket error, Reset Sender's MsgSeqNum to
    // prevent sequence # gaps.  Not doing so will cause Target's request to
    // fill gaps w/Resend Request to fail (as messages not sent aren't
    // logged to the store).
#if ORIG
    if ( !num )
    {
      MsgSeqNum msgSeqNum;
      header.getField( msgSeqNum );
      m_state.set( msgSeqNum, messageString );
      m_state.incrNextSenderMsgSeqNum();
    }
#else
    MsgSeqNum msgSeqNum;
    if ( result )
    {
      if ( !num )
      {
        header.getField( msgSeqNum );
        m_state.set( msgSeqNum, messageString );
        m_state.incrNextSenderMsgSeqNum();
      }
    }
    else
    {
      // reset msg seq num to prevent gaps
      header.getField( msgSeqNum );
      setNextSenderMsgSeqNum( msgSeqNum );
    } /* end if-else */
#endif // #if ORIG

  ...
}

?

Regards,
Brendan