Hi Stephen!
Quote
> On and off I have been aware of threads discussing memory leaks in the
> Borland Delphi2 C/S VCL's.
> Is this true? (I think Yes!)
And you are right! Bounds Checker (www.numega.com) signals that
memory leaks. Ans...
Look, some times ago i found this file at the
Borland's ftp site. Now it missing.
***************************************
README FOR UPDATED DELPHI 2 SYSTEM UNIT
***************************************
The updated System.dcu for Delphi 2.01 addresses two problems:
^^^^^^^^^^^^^^^^^!!!
* The behavior of the FileMode system variable was modified for
greater backward compatibility. Non-text files opened
with Reset() now support all DOS file modes, not only the
documented 0, 1 and 2. In particular, you can now use shared
file modes.
* A bug was fixed in the memory suballocator which caused a
16-byte memory leak for every freed block.
Install the updated System.dcu by copying it to your Delphi 2.0\Lib
directory. Then update your component library by selecting
Component|Rebuild Library from the main menu.
*******************
SOURCE CODE CHANGES
*******************
The GetMem.inc and OpenFile.asm modules were modified to accommodate
the above changes to System.dcu. If you own Delphi Developer or
Delphi Client/Server Suite, then you will find these files in the
...\Delphi 2.0\source\rtl\sys subdirectory.
If you wish to update your installation of the source code to reflect
the changes to System.dcu, then you can follow the directions below
for hand-modification of GetMem.inc and OpenFile.asm.
**********
GETMEM.INC
**********
* Remove FreeBlockDesc() procedure (line 142).
* Replace DeleteBlock() procedure (line 179) with the following code:
procedure DeleteBlock(bd: PBlockDesc);
var
prev, next: PBlockDesc;
begin
prev := bd.prev;
next := bd.next;
prev.next := next;
next.prev := prev;
bd.next := blockDescFreeList;
blockDescFreeList := bd;
end;
* Replace MergeBlockAfter() function (line 190) with the following code:
function MergeBlockAfter(prev: PBlockDesc; const b: TBlock) : TBlock;
var
bd, bdNext: PBlockDesc;
begin
bd := prev.next;
result := b;
repeat
bdNext := bd.next;
if bd.addr + bd.size = result.addr then begin
DeleteBlock(bd);
result.addr := bd.addr;
inc(result.size, bd.size);
end else if result.addr + result.size = bd.addr then begin
DeleteBlock(bd);
inc(result.size, bd.size);
end;
bd := bdNext;
until bd = prev;
if not AddBlockAfter(prev, result) then
result.addr := nil;
end;
* Replace FreeSpace() function (line 303) with the following code:
function FreeSpace(addr: Pointer; maxSize: Integer): TBlock;
// Free at most maxSize bytes of address space at addr.
// Returns the block that was actually freed.
var
bd, bdNext: PBlockDesc;
minAddr, maxAddr, startAddr, endAddr: PChar;
begin
minAddr := PChar($FFFFFFFF);
maxAddr := nil;
startAddr := addr;
endAddr := startAddr + maxSize;
bd := spaceRoot.next;
while bd <> @spaceRoot do begin
bdNext := bd.next;
if (bd.addr >= startAddr) and (bd.addr + bd.size <= endAddr) then
begin
if minAddr > bd.addr then
minAddr := bd.addr;
if maxAddr < bd.addr + bd.size then
maxAddr := bd.addr + bd.size;
if not VirtualFree(bd.addr, 0, MEM_RELEASE) then
heapErrorCode := cReleaseErr;
DeleteBlock(bd);
end;
bd := bdNext;
end;
result.addr := nil;
if maxAddr <> nil then begin
result.addr := minAddr;
result.size := maxAddr - minAddr;
end;
end;
************
OPENFILE.ASM
************
* Replace line 63:
MOV EDX,FILE_SHARE_READ
with the following four lines:
MOV DL,FileMode
AND EDX,070H
SHR EDX,4-2
MOV EDX,dword ptr [@@shareTab+EDX]
* After line 131:
JMP @@exit
and before line 133:
OpenFile ENDP
insert the following nine lines:
@@shareTab:
DD FILE_SHARE_READ OR FILE_SHARE_WRITE ; OF_SHARE_COMPAT
DD 0 ; OF_SHARE_EXCLUSIVE
DD FILE_SHARE_READ ; OF_SHARE_DENY_WRITE
DD FILE_SHARE_WRITE ; OF_SHARE_DENY_READ
DD FILE_SHARE_READ OR FILE_SHARE_WRITE ; OF_SHARE_DENY_NONE
DD 0
DD 0
DD 0
* After line 144:
MOV CL,FileMode
and before line 145:
CMP CL,2
insert the following line:
AND CL,3
=============================================================================
Good luck.
Dmitry.
Moscow.-=RU=-.
