Question

Modify the programs so that each program can both receive and send messages alternatively.

Note that when you run the two programs, you should run them in two different windows ( terminals). You should be able to send messages from one to the other and terminate them by entering "end" //msgl.cpp / Here's the receiver program. / #include #include #include #1nclude #include #include #include Winclude struct my msg st f long int my msg type; char some text [BUFSIz]; ti int main() int runningl; int msgid; truct my msg st some_data; long int msg_ to receive0; First, we set up the message queue. */ msgid msgget ( (key_t)1234, 0666 |IPC CREAT) if (msgid == -1) { fprintf(stderr, "msgget exit (EXIT_FAILURE) failed with %d\n", errno); error: /* Then the messages are retrieved from the queue, until an end message is encountered Lastly, the message queue is deleted. */ while(running) if (msgrcv (msgid, (void )&some data, BUFSIZ, msg to_receive, 0)-1) f fprintf(stderr, "msgrev exit (EXIT FAILURE); failed with %d\n", errno); error: printf( "You wrote: %s", sone, data . some-text); if (strnemp(some data.some text, "end, 3)0) running 0 if (msgctl (msgid, IPC RMID, 0)1) fprintf (stderr, "msgctl (IPC RMID) failedIn) exit (EXIT FAILURE) exit (EXIT SUCCESS); //msg2.cpp /* The sender program is very similar to msgl.cpp. In the main set up, delete the msg to_receive declaration and replace it with buffer [ BUFSIZ], remove the message queue delete and make the following changes to the running loop. We now have a call to msgsnd to send the entered text to the queue. / #include #include #include #include #include #include #include include #define MAX TEXT 512 struct my_msg_st f long int my msg_type; char some_text [MAX_TEXT int main() int running 1; struct my msg_st some_data; int msgid; char buffer [BUFSIZ]; | msgid msgget (( key-t ) 1234, 0666 IPC_CREAT); = if (msgid1) fprintf(stderr , "msgget failed with error : exit (EXIT_FAILURE) %d\n", errno); while(running) printf( "Enter some text: fgets (buffer, BUFSIZ, stdin); some data.my msg type1; strcpy (some_data.some text, buffer) if (msgsnd ( msgid, (void *)&sone, data, MAX-TEXT, 0) -1) { fprintf (stderr, "msgsnd failed\n"); exit (EXIT_FAILURE); if (strncmp (buffer, "end, 3) 0) running0; exit (EXIT_SUCCESS);

Answer 1

//msg1.cpp
/* The sender program is very similar to msg1.cpp. In the main set up, delete th emsg_to recieve declaration and replace it with buffer[BUFSIZ], remove the message queue delete and
make th efollowing changes to the running loop.
we now have a call to msgsnd to send the entered text to the queue */
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<errno.h>
#include<unistd.h>

#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/msg.h>

#define MAX_TEXT 512

struct my_msg_st{
    long int my_msg_type;
    char some_text[MAX_TEXT];
};

int main(){
    int running = 1;
    struct my_msg_st some_data;
    int msgid;
    char buffer[BUFSIZ];
    long int msg_to_receive = 0;
  
    msgid = msgget((key_t)1234, 0666|IPC_CREAT);
  
    if(msgid == -1){
        fprintf(stderr, "msgget failed with error: %d\n", errno);
        exit(EXIT_FAILURE);
    }
  
    while(running){
        printf("Enter some text:");
        fgets(buffer, BUFSIZ, stdin);
        some_data.my_msg_type = 1;
        strcpy(some_data.some_text, buffer);
        if(msgsnd(msgid,(void *)&some_data, MAX_TEXT, 0) == -1){
            fprintf(stderr, "msgsnd failed\n");
            exit(EXIT_FAILURE);
        }
        if(msgrcv(msgid, (void *)&some_data, BUFSIZ, msg_to_receive, 0) == -1){
            fprintf(stderr,"msgrcv failed with error: %d\n", errno);
            exit(EXIT_FAILURE);
        }
        printf("You wrote:%s", some_data.some_text);
        if(strncmp(buffer, "end", 3) == 0){
            running = 0;
        }
    }
    exit(EXIT_FAILURE);
}

//msg1.cpp
/*Here's the receiver program.*/
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<errno.h>
#include<unistd.h>

#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/msg.h>

#define MAX_TEXT 512

struct my_msg_st{
    long int my_msg_type;
    char some_text[BUFSIZ];
};

int main(){
    int running = 1;
    int msgid;
    struct my_msg_st some_data;
    char buffer[BUFSIZ];
    long int msg_to_receive = 0;
  
    /*First, we set up the message queue. */
    msgid = msgget((key_t)1234, 0666 | IPC_CREAT);
    if(msgid == -1){
        fprintf(stderr, "msgget failed with error: %d\n", errno);
        exit(EXIT_FAILURE);
    }
  
    /*Then the messages are retrieved from the queue, until an end message is encountered. last the message queue is deleted. */
    while(running){
        if(msgrcv(msgid, (void *)&some_data, BUFSIZ, msg_to_receive, 0) == -1){
            fprintf(stderr,"msgrcv failed with error: %d\n", errno);
            exit(EXIT_FAILURE);
        }
        printf("You wrote:%s", some_data.some_text);
        printf("Enter some text:");
        fgets(buffer, BUFSIZ, stdin);
        some_data.my_msg_type = 1;
        strcpy(some_data.some_text, buffer);
        if(msgsnd(msgid,(void *)&some_data, MAX_TEXT, 0) == -1){
            fprintf(stderr, "msgsnd failed\n");
            exit(EXIT_FAILURE);
        }
        if(strncmp(some_data.some_text,"end", 3) == 0){
            running = 0;
        }
    }
    if(msgctl(msgid,IPC_RMID,0) == -1){
            fprintf(stderr, "msgctl(IPC_RMID) failed\n");
            exit(EXIT_FAILURE);
    }
  
    exit(EXIT_FAILURE);
}