[fpc-pascal]error messages

[Sidney Cave]

Thanks to Adam Naumowicz for the hint on using
ExitProc for generating descriptive error messages. I
gave that a try and it seems to work fine. This was my
first attempt at writing a unit, and some of this was
by trial and error. If anyone who is interested would
please let me know if I did anything wrong, I would
appreciate it.

Also, is there a procedure for forcing a program to
generate an error of a given type? I took a look at
the docs and could not find anything. It may be there,
but I just don't know what it is called to even to run
a search. I would hesitate to call this little project
done until I could test it by forcing all of the
various errors. As it stands, I only checked two or
three.

Sid Cave
======================================
unit ErrorMsg;
interface
implementation
var
  OldExitProc:pointer;

procedure ErrorMessage;
begin
  if ErrorAddr <> nil then
    begin
      case ExitCode of
        1: writeln ('Invalid function number.');
        2: writeln ('File not found.');
        3: writeln ('Path not found.');
        4: writeln ('Too many open files.');
        5: writeln ('File access denied.');
        6: writeln ('Invalid file handle.');
        12: writeln ('Invalid file access code.');
        15: writeln ('Invalid drive number.');
        16: writeln ('Cannot remove current
directory.');
        17: writeln ('Cannot rename across drives');
        100: writeln ('Disk read error.');
        101: writeln ('Disk write error.');
        102: writeln ('File not assigned.');
        103: writeln ('File not open.');
        104: writeln ('File not open for input.');
        105: writeln ('File not open for output.');
        106: writeln ('Invalid numeric format.');
        150: writeln ('Disk is write-protected.');
        151: writeln ('Bad drive request struct
length.');
        152: writeln ('Drive not ready.');
        154: writeln ('CRC error in data.');
        156: writeln ('Disk seek error.');
        157: writeln ('Unknown media type.');
        158: writeln ('Sector not found.');
        159: writeln ('Printer out of paper.');
        160: writeln ('Device write fault.');
        161: writeln ('Device read fault.');
        162: writeln ('Hardware failure.');
        200: writeln ('Division by zero.');
        201: writeln ('Range check error.');
        202: writeln ('Stack overflow error.');
        203: writeln ('Heap overflow error.');
        204: writeln ('Invalid pointer operation');
        205: writeln ('Floating point overflow.');
        206: writeln ('Floating point underflow.');
        207: writeln ('Invalid floating point
operation.');
        210: writeln ('Object not initialized.');
        211: writeln ('Call to abstract method.');
        212: writeln ('Stream registration error.');
        213: writeln ('Collection index out of
range.');
        214: writeln ('Collection overflow error.');
        216: writeln ('General protection fault.');
        217: writeln ('Unhandled exception
occurred.');
        227: writeln ('Assertion failed error.');
        else writeln ('Unknown error.');
      end;
    end;
  Exitproc:=OldExitProc;
end;

begin
  OldExitProc:=ExitProc;
  ExitProc:=@ErrorMessage;
end.
===================================


=====
Sid Cave
mailto:zcave at yahoo.com

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