How to get current routine line?

I am familiar with $TEXT which can get you any line in the current routine provided you know the offset. For example, $T(+1) will get you the first line of the current routine at the run time. In the same vein, how do I reference the current line number/offset at the run time? Something like $T(+$CURRENTLINENUMBER) where $CURRENTLINENUMBER is not yet known to me function. The sample below would write 3 as the line number.

RTNNAME
 S A=1
W $CURRENTLINENUMBER