Re: System.pas module - Gpc

20 Oct 1996


      Hello Berend, hello everybody!
The system.pas module triggers one bug in GPC concerning
String schemas as parameters:
...
procedure GetDir(D: byte; var s: string);
declares a string schema without specified length as a formal
parameter.  When trying to use it with an actual parameter
which must have a specified length, the compiler crashes.
To work around, always specify string length, e.g.
procedure GetDir(D: byte; var s: string255);
According to Berend de Boer:
...
This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.
Berend, you know that the normal GNU GPL implies that a program
linked with your module automatically becomes free software?
If you want to enable commercial use of your module, either state
explicitely that the above does *not* hold, or use the GNU LGPL
(GNU Library General Public License) instead of the normal GPL.
...
type
  shortint = __byte__ integer;
  byte	   =  __byte__  integer;
That's incompatible with Borland's definition of "byte".
They have
byte = __unsigned__ shortint;
Same holds for "word".
...
TChar	   = array[0..MaxInt] of char;
  PChar	   = TChar;
  pointer  = void;
It must be
PChar   = ^TChar;
    pointer = ^void;
with adaptions below when "PChar" is used.
On my machine, your module compiled (?!;), but "GetDir"
always returned empty strings for this reason.
...
string255= string(255);
var
  {?ExitProc: Pointer;	{ Exit procedure }
Can be implemented using "to end do" and GPC's pointers to procedures.
...
export
  System = (shortint, byte, word, longint, PChar, pointer, string255,
       HeapError, ExitCode, PrefixSeg,
          Assign, BPChDir => ChDir, Close, Copy, Dec, Delete, Erase,
       GetDir, GetMem,
       Inc, IOResult,
       MaxAvail, MemAvail, BPMkDir => MkDir,
          ParamCount, ParamStr,
       BPRename => Rename, BPRmDir => RmDir,
       UpCase);
"Inc", "dec", "GetMem" are in GPC (and couldn't be implemented in a 
module anyway) - and there is no implementation of them in the body.
Yours,
Peter
e-mail:  peter.gerwinski@uni-essen.de
home address:  D"usseldorfer Str. 35, 45145 Essen, Germany
         WWW:  http://agnes.dida.physik.uni-essen.de/~peter/