Why Inno Setup can not load the proc?

Question

I need to call custom dll function in CurStepChanged where CurStep = ssInstall .

[Files]
Source: "publish\InnoSetupHelper.dll"; Flags: dontcopy

[Code]
function StopService(ServiceName: String; TimeOut: Integer): Integer;
external 'StopService@InnoSetupHelper.dll cdecl delayload loadwithalteredsearchpath'; 

procedure CurStepChanged(CurStep: TSetupStep);
var
ErrorCode: Integer;
begin
  case CurStep of
    ssInstall: begin
      ErrorCode := StopService('XxxService', 10000); // line 179
      if ErrorCode <> 0 then
        MsgBox(FmtMessage('Stop service failed: %1', [ErrorCode]), mbCriticalError, MB_OK);
    end;
  end;
end;

EXTERN_C_START

__declspec(dllexport) DWORD StopService(PCWSTR serviceName, DWORD waitStopTimeoutMilliseconds);

EXTERN_C_END

I tried delayload only, loadwithalteredsearchpath only, no delayload and loadwithalteredsearchpath , all not work, either:

or:

Answer 1

1. Your DLL must be 32-bit. Your project has 64-bit target.
2. You should not link against Runtime DLL (or when you do, you have to distribute the Runtime DLL along). I suggest you link the Runtime statically. In project Properties , go to C/C++ > Code Generation > Runtime Library and select Multi-threaded (not DLL ).
3. You are missing files: prefix in your external declaration.