Blocking I/O Model
the most prevalentI/O modelBy default, all sockets areblocking.- With Blocking I/O, system call return when:
- success
- data copied to application space
- error
- interrupted by signal (most common)
- others
- Process
blockedwhen calling these kind of system call.
NonBlocking I/O Model
- when set a socket to be nonblocking
int flags = fcntl(socket, F_GETFL, 0);
fcntl(socket, F_SETFL, flags | O_NONBLOCK);