Error Messages and Codes 

    Errors can be divided up into specific catagories.  The two main
    catagories being Compiler Errors and Runtime Errors.  There is also
    a function for trapping errors associated with the Graph Unit.

    Compiler Errors are those encountered during compile time.  They are
    numbered from 1 to 144 and vary only slightly from version 4.0 of
    Turbo Pascal.  When a Compiler Error is detected, if you are in the
    integrated environment, you are placed back into your source code at
    the point of the error.  The command line compiler displays the error
    message, error number, and the line of source code using the carat (^)
    to point to the error.

    Runtime errors are found during program execution and will usually
    cause the program to terminate.  These errors are further divided
    into four categories: DOS errors 1-99; I/O errors 100-149 (these
    can be controled with the {$I.} directive and the IOresult function);
    Critical Errors 150-199; and Fatal errors 200-255.  When encountered
    they display an error message in this format:

                    Runtime error XXX at XXXX:YYYY

    When using the graphics unit and performing graphics functions, you
    can check error status with the GraphResult function.  This function
    reports the status of the last graphics operation.