Accessing function definitions for UDF

Karl

I notice that some udf's I have seen seem to access functions that I assume are defined as macros by fluent for users to implement. For instance, in a piece of a udf given to me that I am planning to use, the following two lines are written:

Compute_L_sgs(C_VOLUME(c,t),C_WALL_DIST(c,t),C_Cen troid_Y(c,t));

real S = Strainrate_Mag(c,t)

I see in the udf help manual what the functions C_VOLUME(c,t) means, however, I cannot find anywhere any documentation on C_WALL_DIST(), C_Centroid(), or Compute_L_sgs().

Where do I go to find details on each of these functions / variables? The udf manual seems to explain only a limited number of functions for access to the various solver variables?

Thanks in advance.