dllmemu.pas

delphi6从入门到精通随书源码

unit DllMemU;

interface

uses
  Windows, SysUtils;

procedure SetData (I: Integer); stdcall;
function GetData: Integer; stdcall;
procedure SetShareData (I: Integer); stdcall;
function GetShareData: Integer; stdcall;

function GetViewStr(var pViewFlag:Integer): string;stdcall;
implementation

// global DLL data
var
  PlainData: Integer = 0; // not shared
  ShareData: ^Integer; // shared
  hMapFile: THandle;
  ViewStr :array[0..99] of string;
  i:Integer;
  View_Flag :Integer = 0;
const
  VirtualFileName = 'ShareDllData';
  DataSize = sizeof (Integer);


procedure SetData (I: Integer); stdcall;
begin
  PlainData := I;
end;

function GetData: Integer; stdcall;
begin
  Result := PlainData;
end;

// shared data read and write

procedure SetShareData (I: Integer); stdcall;
begin
  ShareData^ := I;
end;

function GetShareData: Integer; stdcall;
begin
  Result := ShareData^;
end;

function GetViewStr(var pViewFlag:Integer): string;stdcall;
begin
  if pViewFlag < 99 then
  begin
    Result :=ViewStr[pviewflag];
    ViewStr[pViewFlag] :='';
    Inc(pViewFlag);
  end
  else
  begin
    pViewFlag :=0;
  end;
end;
initialization
  hMapFile := CreateFileMapping ($FFFFFFFF, nil,
    Page_ReadWrite, 0, DataSize, VirtualFileName);
  if hMapFile = 0 then
    raise Exception.Create ('Error creating memory mapped file');
  ShareData := MapViewOfFile (
    hMapFile, File_Map_Write, 0, 0, DataSize);

  for i := Low(ViewStr) to High(ViewStr) do
    ViewStr[i] :='test Str is' + IntToStr(i);
finalization
  UnmapViewOfFile (ShareData);
  CloseHandle (hMapFile);
end.