#define MASTERPORT 6666
#define SLAVEPORT 6667

struct cmd_msg
 {
   unsigned short num;
   char command,dummy;
   unsigned short line;
   double y,x1,x2;
   unsigned short width;
   unsigned short depth;
 };

struct data_msg
 {
   unsigned short num;
   unsigned short line;
   unsigned char it[0];
 };