Re: Emulating I/O Completion Port on Win98.

From: Alexander Nickolov (agnickolov_at_mvps.org)
Date: 12/06/04 

Date: Mon, 6 Dec 2004 10:39:23 -0800

Either create a separate thread, use non-blocking I/O (select,
WSAEventSelect), or for GUI programs - use async I/O
via Windows messages - WSAAsyncSelect. Overlapped
I/O is also fine, though it has no benefits on Win9x as the
kernel does not support it so it's done entirely in user mode. 

-- 
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://www.mvps.org/vcfaq
=====================================
"Sami" <s8a2m9i1_i5s1l9a6m@hotmail.com> wrote in message 
news:uy24EY52EHA.3616@TK2MSFTNGP11.phx.gbl...
> Hello Arkady,
>
> My Client is an FTP Client and I thought emulating IOCP would be the best
> solution under Win98 to quickly copy a big file from the FTP Server.
>
> What is actually the normal way to receive a big file without blocking the
> client program throughtout the whole time it takes to copy the file from 
> the
> server?
>
> If I just do a WSARecv( ) in a loop till I get the number of bytes of the
> big file then everything else would block.
> -- 
> Regards,
> Sami
>
> [Remove Numbers from e-mail address to use it]
> "Arkady Frenkel" <arkadyf@hotmailxdotxcom> schrieb im Newsbeitrag
> news:OEdLWKV2EHA.3408@tk2msftngp13.phx.gbl...
>> Sami !
>> Why you need IOCP on Client , usually that model is scalable solution for
>> server , not client ?
>> If you client behave as a server to other client you do can use IOCP too 
>> ,
>> but not in the relation with server.
>> Any case look inside...
>>
>> "Sami" <s8a2m9i1_i5s1l9a6m@hotmail.com> wrote in message
>> news:eAdCoz71EHA.3408@tk2msftngp13.phx.gbl...
>> > Hello,
>> > I would like to emulate I/O Completion ports on Win98.
>> > My program is a TCP Client (FTP Client to be more exact) that listens
>> > passively on one port. After the server send a file into the listening
>> > socket I would like to apply an I/O Completion port architecture (on 
>> > the
>> > Client) to handle the downloading of file from FTP Server to the FTP
>> Client.
>> >
>> > Here is a pseudo-code that I have from this newsgroup from  along time
>> ago.
>> > ++++++++++++++++++++++++++++++++++++++++++++++++++++
>> > CIOComplete
>> > {
>> >  typedef struct
>> >  {
>> >   HANDLE hThread; // handle to worker thread;
>> >   MySock * sock;  // the socket need worker thread to handle
>> >   HANDLE hEvent; //  Used to inform the worker thread there is 
>> > operation
>> > need to be performed
>> > } SOCKWORKER;
>> > typedef struct
>> > {
>> >  SOKCET socket;
>> >  OVERLAPPED * overlap;
>> > } MyS***;
>> >  CList<SOCKWORKER> m_list; // worker threads
>> >  CList<MySock> m_listSockets;  // a list of sockets
>> >  BOOL AddSock (MySock sock);
>> > }
>> >
>> > This class works like the following way:
>> >
>> > Several worker threads are spawned and wait on the hEvent. There is a
>> > monitor thread created dedicates to check the IO status of the sockets
> in
>> > m_listSockets. If there is a socket that has read or write operation
>> > performed. The monitor thread will select an idle worker thread and 
>> > fill
>> in
>> > sock and dOperation, then the monitor thread set the hEvent to active
> the
>> > worker thread to handle the socket. After finishing the work, the 
>> > worker
>> > thread will mark sock to zero to indicates it's idle and wait on hEvent
>> > again.
>> >
>> > DWORD WorkerThread (void * ptr)
>> > {
>> >  SOCKWORKER * worker = ptr;
>> >
>> >  while (WaitForSingleObject(worker->hEvent, INFINITE) == WAIT_OBJECT_0)
>> >  {
>> >   If (worker->sock)
>> >   {
>> >    // perform the work
>> > } worker->sock = 0;
>> > } return 0;
>> > }
>> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> >
>> > My questions:
>> > 1) How many sockets should be in the list?
>> In IOCP model the number of sockets is the number of connections and 
>> model
>> desire is to limit number of threads threating those sockets like only 2
>> threads threat few thousands of sockets
>> > 2) Am I correct in thinking that my main( ) is going to create the list
> of
>> > sockets? Or do I need a separate thread to create the list and maintain
>> it?
>> Seems OK
>> > 3) If my TCP Client is listening on one socket (and that is how I want
> it
>> to
>> > be as it is an FTP Client) should I just forward whatever comes into 
>> > the
>> > listening socket to one of the sockets in the list and then flag the
>> worker
>> > thread to take over?
>> That's why I ask you why you need IOCP where huge number of sockets
> treated
>> by few threads.
>> In your case working thread can connect and treat this socket
>> Arkady
>>
>>
>> >
>> > --
>> > Regards,
>> > Sami
>> >
>> > [Remove Numbers from e-mail address to use it]
>> >
>> >
>>
>>
>
>