Since our programs run in a DOS Window, you may at times get an error message. The most typical one is "File not found," or some such. Not to worry, our DOS Error Handler routine will deal with it.

In DOS, if you make a typing mistake, and enter the name of a file that doesn't exist, or leave a drive door open, etc., your PC will beep and you'll get an error message on-screen. It can look like the one shown below. To cause this error, we tried to compute Tanh-1 (-5) while using the Hyperbolics Functions routine.

                Sorry! Error in the Hyperbolics Program

                DOS Error Code # 5
                Reference Line   # 821

                See your DOS Manual for an explanation of the error. A short list of typical DOS errors is given below:

                Error         Translation

                    5            Illegal function call
                    7            Out of memory
                    11          Division by zero
                    27          Out of paper
                    53          File not found
                    61          Disk full
                    64          Bad file name
                    71          Disk not ready
                    76          Path not found         

In the example we show above, DOS Error Code 5 means "Illegal function call."  The reference line number refers to our internal code, and is only listed in the unlikely event that you come across an error you cannot resolve.

To recover from a DOS Window error, follow the on-screen instruction to "Press any Key," and you will be returned to the module where the error occurred.