user1.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <string.h>
#define SERVER 1L
typedef struct {
long msg_to;
long msg_fm;
char buffer[BUFSIZ];
} MESSAGE;
int mid,n;
key_t key;
char buff[50];
struct msqid_ds buf;
MESSAGE msg;
int main(int argc, char** argv) {
key = ftok(".", 'z');
mid = msgget(key, 0);
//Aquiring Message Queue ID
printf("Message Queue ID: %d\n", mid);
printf("user1 ID: %ld\n", (long)getpid());
printf("enter the msg u want to send\n");
scanf("%s",buff);
n=strlen(buff);
int i = 0;
for(i=0;i<=n;i++)
{
msg.buffer[i] = buff[i];
}
//Getting user1 PID and preparing message to message queue
long iD = (long)getpid();
msg.msg_to = SERVER;
msg.msg_fm = (long)getpid();
//Send message to Message Queue for user2, throws and error for invalid input
if(msgsnd(mid, &msg, sizeof(msg.buffer), 0)==-1){
perror("msgsnd");
exit(-1);
}
//Client waits for response from Server, throws an error if invalid input
if(msgrcv(mid, &msg, sizeof(msg), iD, 0)<0){
perror("msgrcv");
exit(-1); }
//Displaying the message received .
printf("Message recieved\n");
printf("%s\n", msg.buffer);
//Removing message queue
msgctl(mid, IPC_RMID, (struct msqid_ds *) 0);
//user1 exits
return (EXIT_SUCCESS);
}