Is there a way to tell if a value was passed on the subroutine CALL statement?

Similar to the earlier thread...
In Fanuc you can tell if a parameter was passed on the call line by checking if value = #0 in the subroutine

But it looks like LinuxCNC just passes all the existing #1...#32 variables from the parent routing to the subroutine, for any not specified on the command line.

So as not to break existing macros, is there a way to submit an enhancement request to add a ?global? variable (e.g. <_param_count> that supplies how many parameters were on the command line?  I see there are parameters to tell the parent routine if there is a return value (#<_value>, #<_value_returned>)