Returns a null terminated C character string which contains the equation associated with node, or the empty string (rather than NULL), if node does not have an equation.

For information on Netica equations, see the "Equation" chapter of Netica Application's onscreen help.

If you need the string to persist, make a copy of the string returned, since its contents may become invalid after further calls to Netica API. Do not try to directly modify or free the string returned.