同时执行recv（）和send（）winsock

Question

I wanted to create a simple chat application with no common server on which to connect to and route their data. However, I don't know how to do it without taking turns, which is odd for a chat program.

I figured I could do multithreading but the information I found so far was just about threading with concern to client requests(to go around the client queue thing). I absolutely haven't tried multithreading before. I also don't know if it's the only way. I also though of doing something event driven but I couldn't make ncurses to work on VS(it linked and compiled successfully but there's something wrong in the library itself, it seems).

So basically how do I make a chat program and not take turns. After all, calling recv() just holds until it receives something so during that time I can't call any stdin functions.

Answer 1

Use an event loop.

1) Did anything happen?

2) If so, handle it.

3) If not, wait for something to happen or for a certain amount of time.

4) Go to step 1.

Now, you just have to make everything that can happen (such as data being received on the socket) an event that you can wait for in step 3. For sockets, you do that with WSAEventSelect . You can wait for events with WaitForMultipleEvents .

Alternatively, you can arrange to have Winsock send your program a Windows message whenever data is received on a socket with WSAAsyncSelect .

Answer 2

Before you call recv, check if data is available. You can use select or poll to use that. See select reference and maybe winsock FAQ .