DLL与EXE之间的通讯调用 以及 回调函数的线程执行空间

  dll 与 exe 之间的通讯方式有很多种， 本文采用回调函数的方法实现， 本文也将研究多线程，多模块的情况下，回调函数所在的线程， 啥也不说了，先附上代码：

下面的是dll模块的的， dll的工程文件：

library DllAPP;

uses
  windows,
  SysUtils,
  Classes,
  DllClass in 'DllClass.pas';

{$R *.res}


 var
  GDllServer: TDllServer;

  function AddServer(ADispatchFunc: TDispatchFunc): HRESULT; stdcall;
  begin
    Result := ERROR_INVALID_FUNCTION;
    if not Assigned(GDllServer) then
      Exit;
    GDllServer.AddServer(ADispatchFunc);
    Result := ERROR_SUCCESS;
  end;

  function DataDispatch(ACommand: Integer):HRESULT; stdcall;
  begin
    Result := ERROR_INVALID_FUNCTION;
    GDllServer.DataDispatch(ACommand);
    Result := 0;
  end;

  function DLLInitialize: HRESULT;
  begin
    Result := 1;
    GDllServer := TDllServer.create;
    Result := ERROR_SUCCESS;
  end;

  function  DllFinalize: HRESULT;
  begin
    Result := ERROR_INVALID_FUNCTION;
    GDllServer.Free;
    GDllServer := nil;
    Result := ERROR_SUCCESS;
  end;

exports
  AddServer,
  DataDispatch,
  DLLInitialize,
  DllFinalize;

begin
end.

dll中的类型文件

unit DllClass;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;


type
  TDispatchFunc = function(ACommand: Integer): HRESULT;stdcall;

type
  TDLLSERVER = CLAss;

  TDLLThread = class(TThread)
  private
    FCount: Integer;
    FDllServer: TDllServer;
  public
    procedure Execute; override;
  public
    constructor create;
  end;

  TDllServer = class
  private
    FDispatchFunc: TDispatchFunc;
    FDllThread: TDLLThread;
  public
    procedure AddServer(ADispatchFunc: TDispatchFunc);
    procedure DataDispatch(ACommand: Integer);
  public
    constructor Create;
    destructor Destroy;
  end;

implementation

{ TDllServer }

///保存exe的回调函数指针
procedure TDllServer.AddServer(ADispatchFunc: TDispatchFunc);
begin
  FDispatchFunc := ADispatchFunc;
end;

constructor TDllServer.create;
var
  LThreadID: Cardinal;
begin
///
  LThreadID := GetCurrentThreadid;
  ShowMessage('DLL,create：'+IntToStr(LThreadID));
  FDllThread := TDLLThread.create;
  FDllThread.FDllServer := Self;
  FDllThread.Resume;
end;

///DLL接受exe传过来的指令， dll留给exe的调用借口
procedure TDllServer.DataDispatch(ACommand: Integer);
var
  LThreadID: Cardinal;
begin
  if not Assigned(FDispatchFunc) then
    Exit;
  FDispatchFunc(ACommand);
  LThreadID := GetCurrentThreadid;
  ShowMessage('DLL,DateDispatch：'+IntToStr(LThreadID));
end;

destructor TDllServer.Destroy;
begin
////
end;

{ TDLLThread }

constructor TDLLThread.create;
var
  LThreadID: Cardinal;
begin
  FCount := 0;
  inherited create(True);
end;

//这个函数的目的就是检验不同模块下的不同线程下，回调函数的执行线程
procedure TDLLThread.Execute;
var
  LThreadID: Cardinal;
begin
  inherited;
  while not Terminated do
  begin
    Inc(FCount);
    if FCount = 2  then
    begin
      LThreadID := GetCurrentThreadid;
      ShowMessage('DLL,Thread--'+IntToStr(LThreadID));
    end;
    if FCount = 5 then
    begin
      if assigned(FDllServer) then
      begin
        FDllServer.FDispatchFunc(2);
      end;

    end;
    Sleep(1000);
  end;
end;

end.

exe的文件

unit ExeClass;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TDispatchFunc = function (ACommand: Integer): HRESULT;stdcall;
  TServerFunc = function (ADispatchFunc: TDispatchFunc): HRESULT;stdcall;
  TProc = function: HRESULT;

type
  TForm2 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    procedure FormDestroy(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
    FServerDispatch: TServerFunc;    ///exe--->dll
    FDataDispatch: TDispatchFunc;    ///EXE--->DLL
    FDllInitialize: TProc;
    FDllFinalize: TProc;
  public
    { Public declarations }
  end;

var
  Form2: TForm2;
  GHandleLibrary: THandle;
  GCount: Integer;

implementation

{$R *.dfm}

///DLL--->EXE，留给dll调用的回调函数
function DataDispatch(ACommand: Integer): HRESULT; stdcall;
var
  LThreadID: Cardinal;
begin
  LThreadID := GetCurrentThreadid;
  ShowMessage('EXE：'+IntToStr(LThreadID));
end;

procedure TForm2.Button1Click(Sender: TObject);
begin
  Inc(GCount);
  FDataDispatch(GCount);
end;

procedure TForm2.FormDestroy(Sender: TObject);
begin
  FDllFinalize;
  FServerDispatch := nil;
  FDataDispatch := nil;
  FDllInitialize := nil;
  FDllFinalize := nil;
  FreeLibrary(GHandleLibrary);
end;

procedure TForm2.FormCreate(Sender: TObject);
var
  LThreadID: Cardinal;
begin
  GHandleLibrary := LoadLibrary(PChar('DLLAPP.dll'));
  @FDllInitialize := GetProcAddress(GHandleLibrary, 'DLLInitialize');
  @FDllFinalize := GetProcAddress(GHandleLibrary, 'DllFinalize');
  @FServerDispatch := GetProcAddress(GHandleLibrary, 'AddServer');
  @FDataDispatch := GetProcAddress(GHandleLibrary,'DataDispatch');
  FDllInitialize;
  FServerDispatch(DataDispatch);
  LThreadID := GetCurrentThreadid;
  Memo1.Lines.Add(IntToStr(LThreadID));
end;

end.

1，简单实现的dll与exe之间的通讯， 其实就是利用了dll的导出函数， 先想dll传递一个回调函数的地址，供dll面向exe的通讯。 exe面向dll 的通讯直接执行dll导出函数即可

2， 本文是最基本的实现，当然其中的回调函数，以及dll的处理函数，可以在数据包的级别上实现， 即： 定义不同数据包，根据命令执行不同的函数， 这样只要导出一个函数，保留一个回调函数 就可以实现大量的功能

3， 关于回调函数的线程执行空间，取决于调用者所在的线程， 比如dll线程中回调exe的函数， 则回调函数是执行在该dll线程。 如果是主线程执行回调，则在主线程。 上述代码GDLLclass的创建过程是导出函数，所以GDLLclass的主线程就是exe的主线程，他们在一个线程空间

http://blog.csdn.net/procedure1984/article/details/3985127