arduino_scheduling.c

typedef int (*CALLABLE) (void);

CALLABLE async_functions[] = {
  xyz,
  yzx,
  zxy,
};

int async_delays[] = {0, 0, 0};
 
void loop() {
  int min_time = 1 << 31,
    min_index = -1;
  for (int i = 0; i < sizeof(async_functions) / sizeof(*async_functions); ++i) {
    if (min_time > async_delays[i]) {
      min_time = async_delays[i];
      min_index = i;
    }
    if (min_time == 0)
      break;
  }
  delay(min_time);
  if (min_time > 0)
    for (int i = 0; i < sizeof(async_functions) / sizeof(*async_functions); ++i)
      async_delays[i] = max(0, async_delays[i] - min_time);
  async_delays[min_index] = async_functions[min_index]();
}