I dont understand ioctlsocket

ioctlsocket() is a general function to do socket control that cannot be done through send() or recv() or select() or similar. (There is also setsockopt())

Mainly, it is a portability shim for functions that on UNIX will go through ioctl(), which is a function that doesn't exist on Windows.

The specific functions of ioctlsocket() depend on the arguments you pass -- there is more than one thing you may be able to do with it. If you have a question about a specific function, mentioning how you are calling it, and what the results are, and what you expect the results to be (copy and paste a few lines of code) is necessary for anyone to be able to help.

i mean if i set a socket to none blocking, what is the diference when you send data to a blocking socket?, i know its set to blocking by default, btw thanks for the fast repyl.

I am following this tutorial

http://www.win32developer.com/tutorial/winsock/winsock_tutorial_4.shtm

i dont know why the developer has the client to recv and the server to send as well?

do you need to set this for both client and server ?

// If iMode!=0, non-blocking mode is enabled.
u_long iMode=1;
ioctlsocket(Socket,FIONBIO,&iMode);

do you need to set this for both client and server ?

These functions have nothing to do with the network. The packets on the network won't change. It only changes how your application (server or client) talks to the network stack. Whether you want to set a socket into non-blocking mode on a client, or on a server, depends on how you write the networking code on your client, or server.

i dont know what you mean by how i write my client and server, how should they be coded?