#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h> 
#include <sys/msg.h>
#include <errno.h>

#include <limits.h>

#define MAXMESGDATA (PIPE_BUF - 2*sizeof(long))
#define MESGHDRSIZE (sizeof(struct mymesg) -MAXMESGDATA)
struct mymesg {
long mesg_len;
long mesg_type;
char mesg_data[MAXMESGDATA];
};
ssize_t mesg_send(int, struct mymesg *);
ssize_t mesg_recv(int, struct mymesg *);