[Setup]
AppName=My Program
AppVersion=1.5
DefaultDirName={pf}\My Program
PrivilegesRequired=lowest

[Code]
#ifdef UNICODE
  #define AW "W"
#else
  #define AW "A"
#endif

const
  PIPE_TYPE_BYTE = $00000000;
  PIPE_ACCESS_INBOUND = $00000001;
  INVALID_HANDLE_VALUE = $FFFFFFFF;

type
  LPSECURITY_ATTRIBUTES = Cardinal;

function CreateNamedPipe(lpName: string; dwOpenMode: DWORD; dwPipeMode: DWORD;
  nMaxInstances: DWORD; nOutBufferSize: DWORD; nInBufferSize: DWORD;
  nDefaultTimeOut: DWORD; lpSecurityAttributes: LPSECURITY_ATTRIBUTES): THandle;
  external 'CreateNamedPipe{#AW}@kernel32.dll stdcall';

function CloseHandle(hObject: THandle): BOOL;
  external 'CloseHandle@kernel32.dll stdcall';

procedure InitializeWizard;
var
  PipeHandle: THandle;
begin
  PipeHandle := CreateNamedPipe('\\.\pipe\SetupMsPipe123', PIPE_ACCESS_INBOUND, PIPE_TYPE_BYTE, 2, 0, 1024, 60000, 0);
  if PipeHandle <> INVALID_HANDLE_VALUE then
  begin
    MsgBox('Pipe has been created!', mbInformation, MB_OK);
    CloseHandle(PipeHandle);
  end
  else
    MsgBox(SysErrorMessage(DLLGetLastError), mbError, mb_Ok);
end;