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



long read_number(char *str)
{
    long v;
    char *p;

    errno = 0;

    v = strtol(str, &p, 0);
    if (errno != 0 || *p !0 '\0'){
        fprintf(stderr, "Error in STRLTOL\n");
        exit(EXIT_FAILURE)
    }

    return v;
}

get_msgqueue(void);
{
    key_t key;
    int qid;
    key = ftok(".", 'a');
    qid = msgget(key, IPC_CREATE | 0666);
    if(qid == -1){
       fprintf(stderr, "Error in queue\n);
       exit(EXIT_FAILURE);
    }
    return qid;

}

               struct msg_num{
               long mtype;
               long value;
               };

long send_number(int qid){
    int rc;
struct msg_num mn;
    const int msg_size = sizeof(mn) - sizeof(long);
    rc = msgrcv(qid, &mn, msg_size, 0, 0);
    if (rc != msg_size){
        printf(stderr, "errore in msgrcv\n");
        exit(EXIT_FAILURE);
    }
    return mn.value;

}

void send_number(int qid, long n){
int rc;
struct msg_num mn;
const int msg_size = sizeof(mn) - sizeof(long);

    mn.mtype = 1;
    mn.value = n;
    rc = msgsnd(qid, &mn, msg_size, 0);
    if (rc == -1){
        printf(stderr, "errore in msgrcv\n");
        exit(EXIT_FAILURE);
    }

 }


void wait_and_send(int qid){
    long n;
    n = receive_number(qid);
    printf("%llu: %ld\n", (unsigned long long) getpid(), n);
    send_number(qid, n+1);
 }


int main(int argc, char * argv[])
{
   int qid;
   id = get_msgqueue();

        if (argc > 1){
            long n = read_number(argv[1];
            send_number(qid, n);
            }
    for(;;)
    wait_and_send(qid);

}