text: #ifndef common_h
  #define common_h
  
  #include <sys/time.h>
  
  typedef unsigned long long timestamp_t;
  
  static timestamp_t get_timestamp ()
  {
    struct timeval now;
    gettimeofday (&now, NULL);
    return  now.tv_usec + (timestamp_t)now.tv_sec * 1000000;
  }
  
  #endif /* common_h */
  