多线程本地图片加载示例【OpenCV】【Pthread】

// ThreadingLoadImages.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include <pthread.h>
#include <opencv2/opencv.hpp>
#define THREADS 3
// Barrier variable
pthread_barrier_t barr;
struct Param
{
  cv::Mat img;
  int index;
  char* file_path;
} params[THREADS];
void* entry_point(void* arg)
{
  Param* p = (Param*)arg;
  int index = p->index;
  char* file_path = p->file_path;
  p->img = cv::imread(file_path);
  printf("The %d thread is doing job! \n", index);
  // Synchronization point
  int rc = pthread_barrier_wait(&barr);
  if (rc != 0 && rc != PTHREAD_BARRIER_SERIAL_THREAD)
  {
    printf("Could not wait on barrier\n");
    exit(-1);
  }
}
int main()
{
  pthread_t thr[THREADS];
  //pthread_mutex_init(&g_mtx, NULL);
  // Barrier initialization
  if (pthread_barrier_init(&barr, NULL, THREADS))
  {
    printf("Could not create a barrier\n");
    return -1;
  }
  //int t[THREADS];
  params[0].file_path = "../micky.png";
  params[1].file_path = "../umbrella.png";
  params[2].file_path = "../beard.jpg";
  for (int i = 0; i < THREADS; ++i)
  {
    //t[i] = i;
    params[i].index = i;
    if (pthread_create(&thr[i], NULL, &entry_point, (void *)&params[i]))
    {
      printf("Could not create thread %d\n", i);
      return -1;
    }
  }
  for (int i = 0; i < THREADS; ++i)
  {
    if (pthread_join(thr[i], NULL))
    {
      printf("Could not join thread %d\n", i);
      return -1;
    }
  }
  printf("All threads finish jobs! \n");
  for(int i=0; i<THREADS; i++)
    cv::imshow(params[i].file_path, params[i].img);
  cv::waitKey(0);
    return 0;
}