Macros for a UNO

I am trying to define a macro to replace the Delay(?)

#define MYWAIT(a) if(millis() > (millisPower + #a)); {}
// called as MYWAIT(100);

and it seems somehow to give an error - can anyone show me where I have gone wrong with this.
Many thanks

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/*
   BLUE TOOTH Throttle application for model railway
   One train driver

   Courtesy of  URB -  Steve Massikker - https://arduinorailwaycontrol.com/
                Arduino - all the Elves
                and me.

   Resources :  https://create.arduino.cc/projecthub/ryanchan/how-to-use-the-l298n-motor-driver-b124c5
                https://www.14core.com/wiring-driving-the-l298n-h-bridge-on-2-to-4-dc-motors/
                https://www.instructables.com/Arduino-2-in-1-Model-Train-Controller/
                Dejan Nedelkovski, www.HowToMechatronics.com

   UNO R3 or Nano v3  with CH340 chip
   L298N      Motor Driver
   HC-05      BLUETOOTH

   Version 1.0 -


    TODO:

    WISH:

*/



//---------------------------------------------------------------
// PINS FOR MOTOR DRIVER -A
#define ENA_PIN 5 // PWM
#define IN1_PIN 7
#define IN2_PIN 8

// LED
#define ledA  A0

// MACROS
#define PRINT_A(a) Serial.println("HELLO:" #a".");
#define PRINT_B(b) Serial.println("WE ARE CONNECTED: "#b".");
#define PRINT_C(c) Serial.println("GOING: "#c".");
#define PRINT_D(d) Serial.println("STOPPED: "#d".");
#define PRINT_E(e) Serial.println("SPEED: "#e".");


#define MYWAIT(a)  if(millis() > (millisPower + #a)); {} // called as MYWAIT(100);


// SPEED              0   1   2   3   4   5   6   7   8   9    10   11   12   13   14   15   16   17   18   19   20   21   22   23   24
byte speedArray [] = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 255};
byte speedTrain = 0;

// USED WITHIN
int counter = 0;
String inputString = "";
static unsigned long millisPower;
bool stringComplete = false;


/////////////////////////// SETUP
void setup () {

   // SET THE SERIAL MONITOR
  Serial.begin(38400); // Default communication rate of the Bluetooth module
  inputString.reserve(4); 
  Serial.print ("File: "); Serial.println(__FILE__);
  Serial.print  (" Date: "); Serial.println(__DATE__);
  Serial.println("------------------------------------------ - ");aa

  // INITIALIZE THE MOTOR DRIVER (A)
  pinMode(ENA_PIN, OUTPUT);
  pinMode(IN1_PIN, OUTPUT);
  pinMode(IN2_PIN, OUTPUT);

  // INITIALIZE THE LED
  pinMode (ledA, OUTPUT);

  // SET THE DEFULT CONDITION
  analogWrite(ENA_PIN, 0);
  digitalWrite(IN1_PIN, LOW);
  digitalWrite(IN2_PIN, LOW);

  // SET THE VARIABLES
  millisPower = millis();


  // BLINK THE LED
  for (int x = 0; x < 3; x++)
  {
    digitalWrite(ledA, HIGH);
    if (millis() > (millisPower + 2500)) {}
    digitalWrite(ledA, LOW);
    if (millis() > (millisPower + 2500)) {}
  }


}


/////////////////////////// LOOP //////////////////////////////////
void loop ()
{
 
  if (Serial.available() > 0)
  { // Checks whether data is comming from the serial port
    inputString = Serial.read(); // Reads the data from the serial port
  }


   // STOPPED
  if (inputString.charAt(0) == 'STP') {
    PRINT_D(PLAYER);
    analogWrite(ENA_PIN, 0);
    counter = 0;
  }

  // DIRECTION
  if (inputString.charAt(0) == 'FWD')  {
    PRINT_C(FORWARD);
    digitalWrite(IN1_PIN, LOW);
    digitalWrite(IN2_PIN, HIGH);
  }

  // DIRECTION
  if (inputString.charAt(0) == 'REV') {
    PRINT_C(REVERSE);
    digitalWrite(IN1_PIN, HIGH);
    digitalWrite(IN2_PIN, LOW);
  }

  MYWAIT(10);

  // SPEED
  if (inputString.charAt(0) == '*') {
    PRINT_E(0) ;
    counter = inputString.charAt(1);
    speedTrain = speedArray[counter];
    analogWrite(ENA_PIN, speedTrain);
  }


}

//////////////////////////// FUNCTIONS /////////////////////////////




//-------------------------------------------------------------
//-------------------------------------------------------------


The error messages are :

`Arduino: 1.8.16 (Windows Store 1.8.51.0) (Windows 10), Board: "Arduino Uno"





















C:\Users\ann\Downloads\Documents\Arduino\Throttle_Blue_1\Throttle_BLUE_1\Throttle_BLUE_1.ino:111:32: warning: character constant too long for its type

   if (inputString.charAt(0) == 'STP') {

                                ^~~~~

C:\Users\ann\Downloads\Documents\Arduino\Throttle_Blue_1\Throttle_BLUE_1\Throttle_BLUE_1.ino:118:32: warning: character constant too long for its type

   if (inputString.charAt(0) == 'FWD')  {

                                ^~~~~

C:\Users\ann\Downloads\Documents\Arduino\Throttle_Blue_1\Throttle_BLUE_1\Throttle_BLUE_1.ino:125:32: warning: character constant too long for its type

   if (inputString.charAt(0) == 'REV') {

                                ^~~~~

C:\Users\ann\Downloads\Documents\Arduino\Throttle_Blue_1\Throttle_BLUE_1\Throttle_BLUE_1.ino: In function 'void setup()':

Throttle_BLUE_1:68:67: error: 'aa' was not declared in this scope

   Serial.println("------------------------------------------ - ");aa

                                                                   ^~

C:\Users\ann\Downloads\Documents\Arduino\Throttle_Blue_1\Throttle_BLUE_1\Throttle_BLUE_1.ino: In function 'void loop()':

C:\Users\ann\Downloads\Documents\Arduino\Throttle_Blue_1\Throttle_BLUE_1\Throttle_BLUE_1.ino:46:51: warning: ISO C++ forbids comparison between pointer and integer [-fpermissive]

 #define MYWAIT(a)  if(millis() > (millisPower + #a)); {} // called as MYWAIT(100);

                                                   ^

C:\Users\ann\Downloads\Documents\Arduino\Throttle_Blue_1\Throttle_BLUE_1\Throttle_BLUE_1.ino:131:3: note: in expansion of macro 'MYWAIT'

   MYWAIT(10);

   ^~~~~~

exit status 1

'aa' was not declared in this scope



This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
``

Suggest you forget this idea.

Make a function or Class.

This is going to be a problem:

;

It's not obvious what your goal is. Are you trying to create a non block delay?? (this would be a programming oxymoron).

Doesn't '#' turn the macro argument into a string? Just leave it off since you want (millisPower + 100) and not of (millisPower + "100").

This is also a concern.
Multicharacter constants are allowed, but they can't be longer than an int, so on the AVRs, that's just two characters.

Thank you John that solved this issue.

Thanks for this info - it also helped me understand macros.

This is what I think you were going for. Sadly, none of the 'if' statements apparently intended to cause delays (macro or otherwise) will cause any delay.

/*
   BLUE TOOTH Throttle application for model railway
   One train driver

   Courtesy of  URB -  Steve Massikker - https://arduinorailwaycontrol.com/
                Arduino - all the Elves
                and me.

   Resources :  https://create.arduino.cc/projecthub/ryanchan/how-to-use-the-l298n-motor-driver-b124c5
                https://www.14core.com/wiring-driving-the-l298n-h-bridge-on-2-to-4-dc-motors/
                https://www.instructables.com/Arduino-2-in-1-Model-Train-Controller/
                Dejan Nedelkovski, www.HowToMechatronics.com

   UNO R3 or Nano v3  with CH340 chip
   L298N      Motor Driver
   HC-05      BLUETOOTH

   Version 1.0 -


    TODO:

    WISH:

*/



//---------------------------------------------------------------
// PINS FOR MOTOR DRIVER -A
#define ENA_PIN 5 // PWM
#define IN1_PIN 7
#define IN2_PIN 8

// LED
#define ledA  A0

// MACROS
#define PRINT_A(a) Serial.println("HELLO:" #a".");
#define PRINT_B(b) Serial.println("WE ARE CONNECTED: "#b".");
#define PRINT_C(c) Serial.println("GOING: "#c".");
#define PRINT_D(d) Serial.println("STOPPED: "#d".");
#define PRINT_E(e) Serial.println("SPEED: "#e".");

// Changed '#a' to 'a' and removed ';'
#define MYWAIT(a)  if(millis() > (millisPower + a)) {} // called as MYWAIT(100);


// SPEED              0   1   2   3   4   5   6   7   8   9    10   11   12   13   14   15   16   17   18   19   20   21   22   23   24
byte speedArray [] = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 255};
byte speedTrain = 0;

// USED WITHIN
int counter = 0;
String inputString = "";
static unsigned long millisPower;
bool stringComplete = false;


/////////////////////////// SETUP
void setup ()
{
  // SET THE SERIAL MONITOR
  Serial.begin(38400); // Default communication rate of the Bluetooth module
  inputString.reserve(4);
  Serial.print ("File: "); Serial.println(__FILE__);
  Serial.print  (" Date: "); Serial.println(__DATE__);
  Serial.println("------------------------------------------ - ");

  // INITIALIZE THE MOTOR DRIVER (A)
  pinMode(ENA_PIN, OUTPUT);
  pinMode(IN1_PIN, OUTPUT);
  pinMode(IN2_PIN, OUTPUT);

  // INITIALIZE THE LED
  pinMode (ledA, OUTPUT);

  // SET THE DEFULT CONDITION
  analogWrite(ENA_PIN, 0);
  digitalWrite(IN1_PIN, LOW);
  digitalWrite(IN2_PIN, LOW);

  // SET THE VARIABLES
  millisPower = millis();

  // BLINK THE LED
  for (int x = 0; x < 3; x++)
  {
    digitalWrite(ledA, HIGH);
    if (millis() > (millisPower + 2500)) {} // This is not going to delay at all
    digitalWrite(ledA, LOW);
    if (millis() > (millisPower + 2500)) {} // This is not going to delay at all
  }
}


/////////////////////////// LOOP //////////////////////////////////
void loop ()
{
  if (Serial.available() > 0)
  {
    // Checks whether data is comming from the serial port
    inputString = Serial.readString(); // Reads the data from the serial port
  }

  // STOPPED
  if (inputString.startsWith("STP"))
  {
    PRINT_D(PLAYER);
    analogWrite(ENA_PIN, 0);
    counter = 0;
  }

  // DIRECTION
  if (inputString.startsWith("FWD"))
  {
    PRINT_C(FORWARD);
    digitalWrite(IN1_PIN, LOW);
    digitalWrite(IN2_PIN, HIGH);
  }

  // DIRECTION
  if (inputString.startsWith("REV"))
  {
    PRINT_C(REVERSE);
    digitalWrite(IN1_PIN, HIGH);
    digitalWrite(IN2_PIN, LOW);
  }

  MYWAIT(10);  // This is not going to delay at all

  // SPEED
  if (inputString[0] == '*')
  {
    PRINT_E(0) ;
    inputString.remove(0, 1); // Remove the '*'
    counter = inputString.toInt();
    speedTrain = speedArray[counter];
    analogWrite(ENA_PIN, speedTrain);
  }
}

//////////////////////////// FUNCTIONS /////////////////////////////

Thank you for the clarification, I was trying to get a handle on how/did macros work - using the Delay(?) as a sample.
Perhaps I should have explained myself a little better on my original post.