IO的4种方式

Blocking IO

{

byte[] buffer = ...

read(socket, buffer); // blocking

process(buffer);

}

 

Non blocking (Sync) IO 

{

byte[] buffer = ...

while ( read(socket, buffer) != 'succeed' ) ; // non blocking but sync

process (buffer);

}

 

Multiplexing blocking IO (blocking, sync or async?, to the socket processing thread, it's sync; to the invoking client, it's async)

{

register(socket);

while (true) {

    sockets = select();// blocking until data is ready for read

    for (s : sockets) {

         if (can_read(s) ) {

            // data is ready, will not be blocked

            read(s, buffer);

            process(buffer);

         }

    }

}

}

 

4. Async Non blocking

{

    register(socket, handleBuffer);

}

 

handleBuffer(buffer) {

    // process

}