delphi动态调用DLL

unit comm;

interface

uses sysutils,dialogs,windows,strutils,classes;

Type
   Tinp32=function(addr:integer):longint;stdcall;
   Tout32=function(addr,data:integer):longint;stdcall;

var
  inp32:tinp32;
  out32:tout32;
  aptr:Tfarproc;
  th:Thandle;
  syspath: array[0..255] of char;

 

implementation

function inp(addr:integer):byte;
begin
    result:=Tinp32(inp32)(addr);
end;

function outp(addr,data:integer):byte;
begin
  result:=Tout32(Out32)(addr,data);
end;

function ExtractRes(ResType, ResName, ResNewName: string): boolean;
 var Res: TResourceStream;
begin
 try
   Res := TResourceStream.Create(Hinstance, Resname, Pchar(ResType));
   try
     Res.SavetoFile(ResNewName);
     Result := true;
   finally
     Res.Free;
   end;
 except
   Result := false;
 end;
end;

procedure ExtractDLL ;
var syspath: array[0..255] of char;
begin
   getsystemdirectory(syspath,255);
   if not FileExists(syspath+'\inpout32.dll') then
   begin
      if not ExtractRes('dllfile','mydll',syspath+'\inpout32.dll') then
         ExtractRes('dllfile','mydll','inpout32.dll');
   end;
end;

initialization

      getsystemdirectory(syspath,255);
      ExtractDLL;
      th:=loadlibrary(pchar(syspath+'\inpout32.dll'));
      if th=0 then th:=loadlibrary('inpout32.dll');
      if(th>0) then begin
        out32:=getProcAddress(th,'Out32');
        inp32:=getProcAddress(th,'Inp32');
      end
      else begin
        raise exception.Create('Load inpout32.dll failed!');
      end;

finalization
      if th>0 then freeLibrary(th);

 

end.