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

#define BUFFSIZE 256

typedef struct{
    long type;
    char data[BUFFSIZE];
} message_t;

int MQ;

void grandkiddyscode(){
    message_t sendMessage;
    sendMessage.type = 100L;
    strcpy(sendMessage.data, "LOS GEHTS!");
    msgsnd(MQ, &sendMessage, BUFFSIZE, 0);

    strcpy(sendMessage.data, "LOS GEHTS ZUM ZWEITEN!");
    msgsnd(MQ, &sendMessage, BUFFSIZE, 0);


    strcpy(sendMessage.data, "Das wars");
    msgsnd(MQ, &sendMessage, BUFFSIZE, 0);
}


void kiddyscode(){
    pid_t i = fork();
    switch(i){
        case -1:
            printf("ERROR: fork()\n");
            exit(1);
        case 0:
            grandkiddyscode();
            exit(0);
            break;
        default:
            break;
    }

    message_t receiveMessage;
    do {
        msgrcv(MQ, &receiveMessage, BUFFSIZE, 100L, 0);
        printf("kiddyscode hat empfangen: %s\n", receiveMessage.data);
    } while(strncmp(receiveMessage.data, "Das wars", 8));
}


int main()
{
    MQ = msgget(IPC_PRIVATE, 0660);

    int i = fork();
    switch(i){
        case -1:
            printf("ERROR: fork()");
            exit(1);
        case 0:
            kiddyscode();
            exit(0);
            break;
        default:
            wait(0);
            break;
    }

    int success = msgctl(MQ, IPC_RMID, 0);

    if(success == -1){
        printf("ERROR: msgctl() - Could not remove message queue!");
    }

    return 0;
}