arduino_pin1.cpp

// struct for pin
typedef struct {
  uint8 pin;
  uint8 state;
  long lastUpdated;
  long interval;  
} pin_info_t;

// initialize pin info
pin_info_t pin9 = {9, LOW, 0, 1000};
pin_info_t pin10 = {10, LOW, 0, 500};
pin_info_t pin11 = {11, LOW, 0, 100};

void setup() {
  for (uint8 pin = 9; pin <= 11; pin++) {
    pinMode(pin, OUTPUT);
  }
}

void loop() {
  /**
   * this is an inline code and would result in duplicated code eventually when compiled
   * we can also define this as a function but a function call will cause a stack manipulation and a JUMP/RETURN instructions
   * which result in slower execution.
   */
  #define PIN_UPDATE(x) \
    if ((timeNow - x.lastUpdated) > x.interval) { \
      x.lastUpdated = millis(); \ // you may use "timeNow" instead, if accuracy is not a case.
      digitalWrite(x.pin, x.state); \ // simply write state via digitalWrite() because HIGH/true are constants defined as 0x01, also LOW/false are 0x00
      x.state = !x.state; \
    }

  // the above inline code refers to this symbol.
  long timeNow = millis();

  PIN_UPDATE(pin9);
  PIN_UPDATE(pin10);
  PIN_UPDATE(pin11);
}