[완료] C++에서 msgrcv( ) 함수가 메시지 올때까지 기다리도록 하고 싶습니다.

#include <stdio.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
 
struct msgbuf msg_data;
 
int main(void)
{
    int msgid = msgget(IPC_PRIVATE, IPC_CREAT|IPC_EXCL|0666);
 
    msgrcv(msgid, &msg_data, 1, 0, 0);
 
    msgctl(msgid, IPC_RMID, 0);
 
    return 0;
}

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
 
class Mythread
{
    public :
        Mythread(void);
        ~Mythread(void);
 
        void init(void);
        void destroy(void);
 
        static void* thread_func(void* arg);
        void* run(void* arg);
 
    private : 
        pthread_t thread_id;
        int msg_id; 
        struct msgbuf msg_data;
 
};
 
Mythread::Mythread(void)
{
 
}
 
Mythread::~Mythread(void)
{
 
}
 
void Mythread::init(void)
{
    int res = 0;
 
    msg_id = msgget(IPC_PRIVATE, IPC_CREAT|IPC_EXCL|0666);
    if (msg_id == -1)
    {
        perror("msg queue creation failed");
        exit(EXIT_FAILURE);
    }
 
    res = pthread_create(&thread_id, NULL, thread_func, (void*) this);
    if (res != 0)
    {
        perror("thread creation failed");
        exit(EXIT_FAILURE);
    }
 
}
 
void Mythread::destroy(void)
{
    int res = 0;
    void* thread_result;
 
    res = msgctl(msg_id, IPC_RMID,0);
    if (res == -1)
    {
        perror("msg destroy failed");
        exit(EXIT_FAILURE);
    }
 
    res = pthread_join(thread_id, &thread_result);
    if (res != 0)
    {
        perror("thread destroy failed");
        exit(EXIT_FAILURE);
    } 
}
 
void* Mythread::thread_func(void* arg)
{
    Mythread *pthread = (Mythread* ) arg;
    return pthread->run(NULL);
}
 
void* Mythread::run(void* arg)
{
    for(int i=0;i<2;i++)
    {
        std::cout << "running in thread..." << std::endl;
        sleep(1);
    }
 
    for(int i=0;i<3;i++)
    {
        size_t data_length = 0;
 
        data_length = msgrcv(msg_id, &msg_data, 1, 0, 0);
        printf("msg id : %d, data_length : %d\n", msg_id, data_length);
 
        std::cout << "received data " << std::endl;
 
    }
 
    pthread_exit(NULL);
}
 
int main(void)
{
    Mythread athread;
 
    athread.init();
    athread.destroy();
 
    std::cout << "Program complete" << std::endl;
    return 0;
}