#include <stdio.h>#include <sys/types.h>#include <sys/ipc.h>#include <sys/msg.h>int main(void){	key_t key;	int msqid;	int proj_id;	key=IPC_PRIVATE;	msqid=msgget(key,0777);	if(msqid==-1)		perror("cannot create message queue");	else		printf("1. key=IPC_PRIVATE, message queue msqid= %d\n",msqid);	proj_id=1;	key=ftok("/home/program",proj_id);	if(key==-1)		perror("cannot generate messge queue key");	msqid=msgget(key,IPC_CREAT|0777);        if(msqid==-1)                perror("cannot create message queue");	else        	printf("2. key=%d generated by ftok, message queue msqid= %d\n",key,msqid);		msqid=msgget(key,IPC_CREAT |IPC_EXCL |0777);	if(msqid==-1)		perror("cannot create message queue");	msqid=msgget(key,IPC_CREAT |0777);	if(msqid==-1)		perror("cannot create message queue");		else		printf("Access the existing message queue\n");	return 0;}