Hello Angus,

Settings the property do not produce the error, it's on .Connect/.Send
that exception raise.


ARMSL> You don't need to send your reply from the event, just make Src a public
ARMSL> variable associated with this specific socket, and use SendTo later.  I
ARMSL> think your issue is trying to set a property, rather than actually
ARMSL> sending a packet. 

ARMSL> Angus

ARMSL> -------- Original Message --------

ARMSL> *Subject:* Re: [twsocket] Force UDP source port when sending
ARMSL> *To:* ICS support mailing <twsocket@elists.org>
ARMSL> *Date:* Sat, 28 Jun 2008 18:06:32 +0200

ARMSL> Hello Angus,

ARMSL> Thank you, so I cannot force the port to same as listening but if I do
ARMSL> it  within  the  OnDataAvailable  then  the .SendTo will automatically
ARMSL> re-use  the same socket to send data back using same src port whenever
ARMSL> this port is actually used for listening by the server ?

ARMSL> So  this also mean that the OnDataAvailable procedure may take a while
ARMSL> to  get  outside if I need to do lenghtly operation. Is there a way to
ARMSL> "keep" this socket to re-use later ?

ARMSL> regards.

>>> So question is : how to force UDP port source when sending it whenever
>>> this port is used by a listener socket as the other application do ?
>>> May be thru sockaddr_in structure ?

ARMSL>> Yes, this is the (simplified) code from the ICS SNTP Time Server
ARMSL> that
ARMSL>> responds to a UDP request with the time to the same IP and port. 

ARMSL>> http://www.magsys.co.uk/download/software/sntp.zip

ARMSL>> Angus

ARMSL>> procedure TTimeServ.WUDPSocketDataAvailable(Sender: TObject;
ARMSL> Error:
ARMSL>> Word);
ARMSL>> var
ARMSL>>     Buffer : array [0..1023] of char;
ARMSL>>     Src    : TSockAddrIn;
ARMSL>>     SrcLen : Integer;
ARMSL>>     NewTime  : LongWord;
ARMSL>>     DataPtr  : TWSocketData ;
ARMSL>> begin
ARMSL>>     SrcLen := SizeOf(Src);
ARMSL>>     FWUDPSocket.ReceiveFrom(@Buffer, SizeOf(Buffer), Src, SrcLen);
ARMSL>>     SrcIPAddr := Src ;
ARMSL>>     NewTime := Trunc ((GetUTCTime - 2) * 24 * 60 * 60) ;
ARMSL>>     ByteSwaps (@NewTime, SizeOf(NewTime)) ;
ARMSL>>     DataPtr := @NewTime ;
ARMSL>>     if FWUDPSocket.Sendto (Src, SrcLen, DataPtr, SizeOf(NewTime))
ARMSL>>             SOCKET_ERROR then
ARMSL> TriggerQueryDone(FWUDPSocket.LastError);
ARMSL>> end;

ARMSL> -- 
ARMSL> To unsubscribe or change your settings for TWSocket mailing list
ARMSL> please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket
ARMSL> Visit our website at http://www.overbyte.be

To unsubscribe or change your settings for TWSocket mailing list
please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket
Visit our website at http://www.overbyte.be

Reply via email to