使用C语言pthreads多线程计算词频总和，需用mutex解决计数问题

我正在运行三个线程，尝试计算每个单词的总出现频率，需要使用mutex来避免计数错误。

运行输出结果 #

57848 index is 0
37389 index is 1
8447 index is 2
10016 index is 3
2756 index is 4

统计结果 #

• he -> 57848
• she -> 37389
• they -> 8447
• him -> 10016
• me -> 2756

相关代码片段 #

void threadfunc(char *path, char *filetowrite, long specialfreq[], int num_threads){

  DIR* dir = opendir(path);
  if(dir == NULL){ return; }
  struct dirent* entity;
  entity = readdir(dir);

  
  for (int i = 0; i < num_threads; i++) {
    if (pthread_join(thread_id[i],  NULL) != 0) {
      perror("Failed to join thread");
    }
  }
}

内容的提问来源于stack exchange，提问作者user19603927