DELPHI FAQ: Как вызывать функцию 16-битной DLL из 32-битного приложения?

Как вызывать функцию 16-битной DLL из 32-битного приложения?

Надо использовать Thunks.

Кусок работающего только под Windows 95 кода -

const
   Gfsr_SystemResources = 0;
   Gfsr_GdiResources = 1;
   Gfsr_UserResources = 2;
var
   hInst16: THandle;
   GFSR: Pointer;
{ Undocumented Kernel32 calls. }
function LoadLibrary16(LibraryName: PChar): THandle; stdcall; external kernel32 index 35;
procedure FreeLibrary16(HInstance: THandle); stdcall; external kernel32 index 36;
function GetProcAddress16(Hinstance: THandle; ProcName: PChar): Pointer; stdcall; external kernel32 index 37;
procedure QT_Thunk; cdecl; external kernel32 name 'QT_Thunk';
{ QT_Thunk needs a stack frame. }
{$StackFrames On}
{ Thunking call to 16-bit USER.EXE. The ThunkTrash argument
allocates space on the stack for QT_Thunk. }
function NewGetFreeSystemResources(SysResource: Word): Word;
var
   ThunkTrash: array[0..$20] of Word;
begin
   { Prevent the optimizer from getting rid of ThunkTrash. }
   ThunkTrash[0] := hInst16;
   hInst16 := LoadLibrary16('user.exe');
   if hInst16 < 32 then
     raise Exception.Create('Cannot load USER.EXE!');
   { Decrement the usage count. This doesn't really free the
     library, since USER.EXE is always loaded. }
   FreeLibrary16(hInst16);
   { Get the function pointer for the 16-bit function in USER.EXE. }
   GFSR := GetProcAddress16(hInst16, 'GetFreeSystemResources');
   if GFSR = nil then
     raise Exception.Create('Cannot get address of GetFreeSystemResources!');
   { Thunk down to USER.EXE. }
   asm
     push SysResource { push arguments }
     mov edx, GFSR { load 16-bit procedure pointer }
     call QT_Thunk { call thunk }
     mov Result, ax { save the result }
   end;
end;
Автор - Quality freeware from Sight&Sound, Slovenia : http://www.sight-sound.si

Андрей Гусев (Andrey Gusev)

Взято из Akzhan's Delphi-related VCL&WinAPI Tips'n'Tricks

Посылаю код для определения системных ресурсов (как в "Индикаторе ресурсов"). Использовалась статья "Calling 16-bit code from 32-bit in Windows 95".

{ GetFeeSystemResources routine for 32-bit Delphi.

Works only under Windows 9x }

unit SysRes32;

interface

const
//Constants whitch specifies the type of resource to be checked

GFSR_SYSTEMRESOURCES = $0000;
GFSR_GDIRESOURCES    = $0001;
GFSR_USERRESOURCES   = $0002;

// 32-bit function exported from this unit

function GetFeeSystemResources(SysResource: Word):Word;

implementation

uses

SysUtils, Windows;

type

//Procedural variable for testing for a nil

TGetFSR = function(ResType: Word): Word; stdcall;

//Declare our class exeptions

EThunkError = class(Exception);
EFOpenError = class(Exception);

var

User16Handle : THandle = 0;
GetFSR       : TGetFSR = nil;

//Prototypes for some undocumented API

function LoadLibrary16(LibFileName: PAnsiChar): THandle; stdcall;
external kernel32 index 35;

function FreeLibrary16(LibModule: THandle): THandle; stdcall;
external kernel32 index 36;

function GetProcAddress16(Module: THandle; ProcName: LPCSTR): TFarProc;stdcall;
external kernel32 index 37;

procedure QT_Thunk; cdecl;
external 'kernel32.dll' name 'QT_Thunk';

{$StackFrames On}

function GetFeeSystemResources(SysResource: Word):Word;
var

EatStackSpace: String[$3C];
begin
// Ensure buffer isn't optimised away

EatStackSpace := '';
@GetFSR:=GetProcAddress16(User16Handle,'GETFREESYSTEMRESOURCES');
if  Assigned(GetFSR) then  //Test result for nil
asm
//Manually push onto the stack type of resource to be checked first

push  SysResource
//Load routine address into EDX

mov   edx, [GetFSR]
//Call routine

call  QT_Thunk
//Assign result to the function

mov   @Result, ax
end
else raise EFOpenError.Create('GetProcAddress16 failed!');
end;

initialization

//Check Platform for Windows 9x
if Win32Platform <> VER_PLATFORM_WIN32_WINDOWS then

raise EThunkError.Create('Flat thunks only supported under Windows 9x');

//Load 16-bit DLL (USER.EXE)
User16Handle:= LoadLibrary16(PChar('User.exe'));

if User16Handle < 32 then
raise EFOpenError.Create('LoadLibrary16 failed!');

finalization

//Release 16-bit DLL when done
if User16Handle <> 0 then

FreeLibrary16(User16Handle);

end.

Взято с www.delphiworld.narod.ru

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