Checking the pin status with if or M66 ?

Hi my friends
I need to learn how to use "if" by checking the parallel port's pin's status.

I am trying to write a line such as ;

If (parallel port pin 10 == true )
Codes here....
Endif

And i think this lines cannbe done by m66, but i couldnt.
I define pins 10 as p0 and i write ;
M66 P0 L3 Q5 to wait the high input for 5 secs.
After 5 seconds it continues the rests of the code. But i need not to continue.


Can anyone help me with this issue?

If you search 'pin value gcode' in the left hand search bar, you will get these amoungst others

linuxcnc.org/index.php/english/forum/10-...ing-hal-pin-from-ngc

linuxcnc.org/index.php/english/forum/22-...a-to-g-code-variable