IOResult                 Returns I/O Error Status

 IOResult : Integer;                                                     [TP]

    Returns the input/output (I/O) error status. To use this, you must
    first disable automatic I/O error checking using the {$I-} compiler
    directive. Having done that, you should reference the value of
    IOResult after each I/O operation. If IOResult returns 0, the I/O
    operation was successful. Any other value returned by IOResult means
    an error occurred. If an I/O error occurs and IOResult is not called,
    all I/O is suspended until IOResult is called.

          Notes:    After IOResult is called, any new calls to IOResult
                    return 0 until the next I/O operation is performed.

                    See 'I/O Errors' for a list of I/O Errors.

  -------------------------------- Example ---------------------------------

      { The following procedure performs crash-proof integer input }

           type
             MsgStr  = string[80];
           ...
           procedure GetInteger(var I : Integer; Msg : MsgStr; Low,High :
           Integer);

             begin {$I-}            { disable I/O error checking }
               I := Low - 1;
               repeat
                 Write(Msg);
                 Readln(I);
               until (IOResult = 0) and (Low <= I) and (I <= High)
             end;  {$I+}            { enable I/O error checking }

           GetInteger(I,'Enter a number from 1 to 10:  ',1,10);