text: // main.cpp
  // Lets Arduino RadioHead sketches run within a simulator on Linux as a single process
  // Copyright (C) 2014 Mike McCauley
  // $Id: simMain.cpp,v 1.2 2014/05/09 05:30:03 mikem Exp mikem $
  
  #include <stdio.h>
  #include <RHutil/simulator.h>
  #include <sys/time.h>
  #include <unistd.h>
  #include <time.h>
  
  SerialSimulator Serial;
  
  // Functions we expect to find in the sketch
  extern void setup();
  extern void loop();
  
  // Millis at the start of the process
  unsigned long start_millis;
  
  int    _simulator_argc;
  char** _simulator_argv;
  
  // Returns milliseconds since beginning of day
  unsigned long time_in_millis()
  {    
      struct timeval te; 
      gettimeofday(&te, NULL); // get current time
      unsigned long milliseconds = te.tv_sec*1000LL + te.tv_usec/1000; // caclulate milliseconds
      return milliseconds;
  }
  
  // Run the Arduino standard functions in the main loop
  int main(int argc, char** argv)
  {
      // Let simulated program have access to argc and argv
      _simulator_argc = argc;
      _simulator_argv = argv;
      start_millis = time_in_millis();
      // Seed the random number generator
      srand(getpid() ^ (unsigned) time(NULL)/2);
      setup();
      while (1)
  	loop();
  }
  
  void delay(unsigned long ms)
  {
      usleep(ms * 1000);
  }
  
  // Arduino equivalent, milliseconds since process start
  unsigned long millis()
  {
      return time_in_millis() - start_millis;
  }
  
  long random() {
  	return rand();
  }
  
  long random(long from, long to)
  {
      return from + (random() % (to - from));
  }
  
  long random(long to)
  {
      return random(0, to);
  }
  