ErrorFlagCD and ErrorMessageCD
ErrorFLagCL is a global int variable used by the
mathematical functions to signal an error. If an error occurs, ErrorFlagCD
will be set to be true and the global char* variable
ErrorMessageCD will point to a relevant error message. This may
be displayed via ErrorCL(ErrorMessageCD).
boolean
CCATSL defines the boolean type as unsigned char, and the constants
true as 1, and false as 0.