Using an output pin as a boolean flag

Configured pin

[output_pin statex]
pin: PC11
value: 1

Reading pin state and doing something based on value

[macro DO_STUFF_IF_OTUPUT_PIN_1]
gcode:
  
    G0 X20
  

Writing pin state

[macro CHANGE_PIN_STATEX]
gcode:
  SET_PIN PIN=statex VALUE=0