program1

#include <sys/types.h>

#include <sys/ipc.h>

#include <sys/msg.h>

#include <string.h>

#include <stdio.h>

#include <stdlib.h>

#define LAST_MESSAGE 255 

​

int main() {

    int msqid; 

    char pathname[] = "./test"; 

    key_t key; 

    int i,len, maxlen; 

    struct mymsgbuf

    { 

        long mtype;

        char mtext[90]; 

    } mybuf;

​

    if((key = ftok(pathname,0)) < 0){

        printf("Can\'t generate key\n");

        exit(-1);

    }

​

    if((msqid = msgget(key, 0777 | IPC_CREAT)) < 0){

        printf("Can\'t get msqid\n");

        exit(-1);

    } 

​

    for (i = 1; i <= 5; i++){

​

        mybuf.mtype = 1;

        strcpy(mybuf.mtext, "This is text message from program1");

        len = strlen(mybuf.mtext)+1;

​

        if (msgsnd(msqid, (struct msgbuf *) &mybuf, len, 0) < 0){

            printf("Can\'t send message to queue\n");

            msgctl(msqid, IPC_RMID, 

                (struct msqid_ds *) NULL);

            exit(-1);

        }

    }

    mybuf.mtype = LAST_MESSAGE;

    len = 0;

    if (msgsnd(msqid, (struct msgbuf *) &mybuf, len, 0) < 0){

        printf("Can\'t send message to queue\n");

        msgctl(msqid, IPC_RMID, 

            (struct msqid_ds *) NULL);

        exit(-1);

    }

​

    while(1){

        maxlen = 90;

        if ( len = msgrcv(msqid, (struct msgbuf *) &mybuf, maxlen, 0, 0) < 0){

            printf("Can\'t receive message from queue\n");

            exit(-1);

        }

        if (mybuf.mtype == LAST_MESSAGE){

            msgctl(msqid, IPC_RMID, 

            (struct msqid_ds *) NULL);

            exit(0);

        }

        if (mybuf.mtype == 2) {

            printf("message type = %ld, info = %s\n", mybuf.mtype, mybuf.mtext);

        }

    }

​

    return 0;

}