Lv4. 쓰레드 순서 지키기

#include <pthread.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/stat.h>
#include <regex.h>

#include <fcntl.h>
#include <string.h>

#define ThreadNum 4

pthread_mutex_t mutex_lock;
pthread_cond_t  sync_cond;

pthread_mutex_t gmutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t  gcond  = PTHREAD_COND_INITIALIZER;

struct Data
{
  int msgtype;
  int id;
  char data[8];
  key_t key_id;
};

void *Tfunction(void *data)
{
  struct Data lData;
  int myid;

  lData = *(struct Data *)data;

  // 쓰레드 동기화
  pthread_mutex_lock(&mutex_lock);
  usleep(1000);
  pthread_cond_signal(&sync_cond);
  pthread_mutex_unlock(&mutex_lock);

  myid = lData.id;
  while(1)
  {
    if(msgrcv(lData.key_id, (void *)&lData, sizeof(lData), lData.id, 0) == -1)
    {
      perror("msgrcv thread error: ");
    }
    if (myid < ThreadNum)
    {
      lData.msgtype = myid+1;
    }
    else
    {
      lData.msgtype = 1;
    }
    lData.id = myid;
    if(msgsnd(lData.key_id, (void *)&lData, sizeof(lData), IPC_NOWAIT) <0)
    {
      perror("msg snd error");
      exit(0);
    }
    printf("Thread Num %d\n", myid);
    usleep(100);
  }
}

int main(int argc, char **argv)
{
  struct Data lData;

  pthread_t p_thread[ThreadNum];

  // Message queue
  key_t key_id;

  // 메시지큐 생성
  key_id = msgget((key_t)8888, IPC_CREAT|0666);
  if (key_id == -1)
  {
    perror("msgget error : ");
    exit(0);
  }

  for (int i = 0; i < ThreadNum; i++)
  {
    lData.msgtype = i+1;
    lData.id = i+1;
    lData.key_id = key_id;

    printf("Create Thread %d\n", lData.id);
    pthread_mutex_lock(&mutex_lock);
    pthread_create(&p_thread[i], NULL, Tfunction, (void *)&lData);
    pthread_cond_wait(&sync_cond, &mutex_lock);
    pthread_mutex_unlock(&mutex_lock);
  }
  lData.msgtype = 1;
  if(msgsnd(key_id, (void *)&lData, sizeof(lData), IPC_NOWAIT) <0)
  {
    perror("msg main snd error");
    exit(0);
  }
  while(1)
  {
    sleep(1);
  }
}