MFCAsync: Message-Oriented TCP and Multithreaded Client/Server

ID: Q192570

The information in this article applies to:

The Microsoft Foundation Classes (MFC)

SUMMARY

MFCAsync.exe contains a Visual C++ 5.0 project sample that shows the communication techniques between a client (AsyncClient) and a server (AsyncServer) application using MFC CAsyncSocket class on each sides.

Here are some highlights of this sample:

MFCAsync.exe follows KB article Q175668, showing the use of Transmission Control Protocol (TCP) socket communication in a separate thread other than the Graphics User Interface (GUI) thread; as such, the blocking of the GUI message pump does not affect the delivery of socket messages. Multiple instances of AsyncClient can talk to the same instance of AsyncServer.

MFCAsync.exe also complies with KB Article Q185728 in issuing of socket Send and Receive calls.

MFCAsync.exe adds message boundary on top of the stream-oriented TCP. Each message is sent with a 4-byte-length packet header followed by the body of the message. Users can append more customized packet header fields to this length field.

MORE INFORMATION

The following file(s) are available for download from the Microsoft Software Library:

~ MFCAsync.exe

Release Date: 07-31-1998

For more information about downloading files from the Microsoft Software Library, please see the following article in the Microsoft Knowledge Base:

Q119591 How to Obtain Microsoft Support Files from Online Services

The flow of logic:

AsyncServer listens on port 9898.

AsyncClient spawns a thread, which connects to the AsyncServer.

AsyncServer accepts the connection and spawns a thread to handle the socket communication.

AsyncClient sends data packet to AsyncServer.

AsyncServer receives and sends the same data packet back to AsyncClient.

AsyncClient receives data packet, reverses the data packet and sends back to AsyncServer.

Repeat steps 5 and 6 until being disconnected either by the AsyncClient or AsyncServer.

Steps to run the sample:

Run AsyncServer.exe on machine A.

Run AsyncClient.exe either on machine A or machine B.

On the AsyncClient side, enter the server machine name where AsyncServer is running. Click Connect. Enter text in the Send edit box. Click Send.

When you are done with the test, click Disconnect on the AsyncClient side.

REFERENCES

For more information, please see the following articles in the Microsoft Knowledge Base:

Q175668 FILE: MultiSoc: Illustrates Using Sockets in Multiple Threads

For more information about downloading files from the Microsoft Software Library, please see the following article in the Microsoft Knowledge Base:

Q185728 SAMPLE: MFCSocs.exe Avoids Two Common MFC Socket Mistakes

Additional query words: CAsyncSocket multithreaded socket thread message


Keywords          : kbnetwork kbAPI kbMFC kbWinOS95 kbWinOS98 kbWinsock kbGrpNet 
Version           : WINNT:
Platform          : winnt 
Issue type        :

Last Reviewed: July 21, 1999