BPCOMPAT v1.10 -released!_(re)

Thu, 23 Oct 1997 02:42:29 +0200

Some minor comments:

Unit system:

The type declarations (especially string=bpstring with -D_Borland_Pascal_
should be in system.pas itself (or $included) rather than in a separate unit
(gpctypes.pas) so that programs that use only system will see them.

My suggestion: remove the "{$W-}". Doing so will reveal a little bug in BinEof
(a "=" used instead of ":="), and a lot of problem in FillChar and Move
(which are not really portable, anyway). Until a (more optimized) version
of them will be built in, here are some replacements (a bit slower, but
should be portable and generate no warnings):

Procedure FillChar ( Var Dest : Void; Count : Integer; C : Char );
Var z:Integer;
begin
  for z:=0 to Count-1 do TCharArray(Dest)[z] := C
end;

Procedure Move ( Var Source, Dest : Void; Count : Integer );
Const PtrBitSize = BitSizeOf(Pointer);
Type PtrCard = Cardinal(PtrBitSize);
Var z:Integer;
begin
  { Avoid overwriting of overlapping memory areas }
  if PtrCard (@Source) > PtrCard (@Dest)
    then for z:=0 to Count-1 do TCharArray(Dest)[z] := TCharArray(Source)[z]
    else for z:=Count-1 downto 0 do TCharArray(Dest)[z] := TCharArray(Source)[z]
end;

To make it work, you have to remove the (now obsolete) declaration of
Cardinal (and perferably ByteInt and Byte as well) from gpctypes.pas.

For the other type declarations, I suggest you use the more modern GPC integer
types (as invented some months ago), rather than the old style __modifiers__.
(Also for real types.)

With -D_Borland_16_Bit_, also redeclare Integer to be a 16 bit type,
otherwise it'll probably confuse some BP programs.

A test program for FillChar and Move:

program x;
uses system;

var 
  a:array[1..20] of char;
  b:integer;

begin
  a:='foo';
  fillchar(a[3],10,'x');
  writeln(a);
  move(a[1],a[10],5);
  writeln(a);
  move(a[10],a[2],3);
  writeln(a)
end.

The correct output is:
foxxxxxxxxxx
foxxxxxxxfoxxx
ffoxxxxxxfoxxx

Procedures assgined to procedural variables can be in the main program now,
so you can remove this comment for ExitProc.

I think it's not a good idea to declare BP variables like ErrorAddr that are
not implemented in GPC. I'd prefer a compile time error when porting a BP
program using them rather than possible unexpected problems at runtime.

Assign is built-in now, so you can remove it from system.pas.
Str, Val, Insert and Delete will be soon... :-), perhaps also Pos, Copy,
ParamCount, ParamStr, Int and Frac.

Unit Dos:

SearchRec, FindFirst, FindNext and GetEnv are not really BP compatible
(also note the difference between SearchRec and TSearchRec in BP).

SwapVectors should be declared as an empty procedure.

Unit Printer:

can be written now (at least for DJGPP).

-- 
Frank Heckenbach, Erlangen, Germany
heckenb@mi.uni-erlangen.de
http://home.pages.de/~fjf/links.htm

Frank Heckenbach (heckenb@mi.uni-erlangen.de)