All ardlib functions return a value, either an integer or a
pointer. Unless otherwise specified, those that return integers will
0 to indicate success, or
-1 to indicate an error. Those that
return pointers will return
NULL to indicate an error. For
the sake of clarity, error checking code has been omitted in many of
the examples that follow.
Some of the functions take arguments representing energies. The energy unit assumed by ardlib is keV. Similarly, areas are assumed to have units of square cm, and angles are specified in radians.