Question

I have this definition

#define LED_CLOCK_PIN (DDRD, PORTD, PD6)

I want to write two more definitions, in order to get PORTD and PD6 values, something like this

#define GET_PORT(_PORT_) /*some magic goes here*/
#define GET_PIN(_PIN_) /*some magic goes here*/

uint8_t port = GET_PORT(LED_CLOCK_PIN);
uint8_t pin = GET_PIN(LED_CLOCK_PIN);

Is it possible?

Answer 1

Do you mean something like:

#define LED_CLOCK_PIN (DDRD, PORTD, PD6)

#define SND(A, B, C) B
#define GET_PORT(X) SND X

uint8_t port = GET_PORT(LED_CLOCK_PIN);

gcc -E processes it to uint8_t port = PORTD;. I’m not sure if this is fully portable and guaranteed by standard.