#ifndef SFSOURCE_H#define SFSOURCE_Hint open_sf_source(const char *host, int port);/* Returns: file descriptor for serial forwarder at host:port, or     -1 for failure     (see init_sf_source for description of platform handling) */int init_sf_source(int fd);/* Effects: Checks that fd is following the serial forwarder protocol.     Use this if you obtain your file descriptor from some other source     than open_sf_source (e.g., you're a server)     Sends 'platform' for protocol version '!', and sets 'platform' to     the received platform value.   Modifies: platform   Returns: 0 if it is, -1 otherwise */void *read_sf_packet(int fd, int *len);/* Effects: reads packet from serial forwarder on file descriptor fd   Returns: the packet read (in newly allocated memory), and *len is     set to the packet length*/int write_sf_packet(int fd, const void *packet, int len);/* Effects: writes len byte packet to serial forwarder on file descriptor     fd   Returns: 0 if packet successfully written, -1 otherwise*/#endif