result = FD_ISSET (socket, bitmask)
int result, socket;
fd_set *bitmask;
result FD_ISSET()
result 1
socket result 0
socket
bitmask fd_set
FD_SET (socket, bitmask)
int socket;
fd_set *bitmask;
socket
bitmask fd_set
FD_ZERO (bitmask)
fd_set *bitmask;
bitmask fd_set