Class CSocket derives from CAsyncSocket and inherits its encapsulation of the Windows Sockets API. A CSocket object represents a higher level of abstraction of the Windows Sockets API than that of a CAsyncSocket object. CSocket works with classes CSocketFile and CArchive to manage the sending and receiving of data.
A CSocket object also provides blocking, which is essential to the synchronous operation of CArchive. Blocking functions, such as Receive, Send, ReceiveFrom, SendTo, and Accept (all inherited from CAsyncSocket), do not return a WSAEWOULDBLOCK error in CSocket. Instead, these functions wait until the operation completes. Additionally, the original call will terminate with the error WSAEINTR if CancelBlockingCall is called while one of these functions is blocking.
To use a CSocket object, call the constructor, then call Create to create the underlying SOCKET handle (type SOCKET). The default parameters of Create create a stream socket, but if you are not using the socket with a CArchive object, you can specify a parameter to create a datagram socket instead, or bind to a specific port to create a server socket. Connect to a client socket using Connect on the client side and Accept on the server side. Then create a CSocketFile object and associate it to the CSocket object in the CSocketFile constructor. Next, create a CArchive object for sending and one for receiving data (as needed), then associate them with the CSocketFile object in the CArchive constructor. When communications are complete, destroy the CArchive, CSocketFile, and CSocket objects. The SOCKET data type is described in the article Windows Sockets: Background in Visual C++ Programmer’s Guide.
For more information, see Windows Sockets in MFC, Windows Sockets: Using Sockets with Archives, Windows Sockets: How Sockets with Archives Work, Windows Sockets: Sequence of Operations, Windows Sockets: Example of Sockets Using Archives, and related articles in Visual C++ Programmer’s Guide. Also see Overview of Windows Sockets 2 and Windows Sockets Programming Considerations in the Win32 SDK documentation.
#include <afxsock.h>
Class Members | Base Class | Hierarchy Chart
Sample MFC Sample CHATSRVR
See Also CAsyncSocket, CSocketFile