=for hackers
Found in file sv.h
+=item SvGAMAGIC
+X<SvGAMAGIC>
+
+Returns true if the SV has get magic or overloading. If either is true then
+the scalar is active data, and has the potential to return a new value every
+time it is accessed. Hence you must be careful to only read it once per user
+logical operation and work with that returned value. If neither is true then
+the scalar's value cannot change unless written to.
+
+ char* SvGAMAGIC(SV* sv)
+
+=for hackers
+Found in file sv.h
+
=item SvGROW
X<SvGROW>