The netbuf_open function opens a new network buffer and returns it. You can use netbuf_open to create a netbuf structure and start using buffered I/O on a socket.
netbuf* netbuf_open(SYS_NETFD sd, int sz);
A pointer to a new netbuf network buffer structure.
SYS_NETFD sd is the platform-independent identifier of the socket.
int sz is the number of characters to allocate for the network buffer.