t.Errorf("got %f want 2.5 (err=%v)", dr, err)
	}
}

func TestTimeBeginPeriod(t *testing.T) {
	const TIMERR_NOERROR = 0
	if *runtime.TimeBeginPeriodRetValue != TIMERR_NOERROR {
		t.Fatalf("timeBeginPeriod failed: it returned %d", *runtime.TimeBeginPeriodRetValue)
	}
}

// removeOneCPU removes one (any) cpu from affinity mask.
// It returns new affinity mask.
func removeOneCPU(mask uintptr) (uintptr, error) {

//sys	DwmSetWindowAttribute(hwnd HWND, attribute uint32, value unsafe.Pointer, size uint32) (ret error) = dwmapi.DwmSetWindowAttribute

// Windows Multimedia API
//sys TimeBeginPeriod (period uint32) (err error) [failretval != 0] = winmm.timeBeginPeriod
//sys TimeEndPeriod (period uint32) (err error) [failretval != 0] = winmm.timeEndPeriod

// syscall interface implementation for other packages

		if m32 == 0 {
			print("runtime: LoadLibraryExW failed; errno=", getlasterror(), "\n")
			throw("winmm.dll not found")
		}
		_timeBeginPeriod = windowsFindfunc(m32, []byte("timeBeginPeriod\000"))
		_timeEndPeriod = windowsFindfunc(m32, []byte("timeEndPeriod\000"))
		if _timeBeginPeriod == nil || _timeEndPeriod == nil {
			print("runtime: GetProcAddress failed; errno=", getlasterror(), "\n")

// On Windows version 1803 and newer, the resolution is ~0.5ms.
// On older Windows versions, the default resolution is ~16ms, but
// a higher resolution may be requested using [golang.org/x/sys/windows.TimeBeginPeriod].
package time

import (
	"errors"
	_ "unsafe" // for go:linkname
)

// A Time represents an instant in time with nanosecond precision.
//

	procVerQueryValueW                                       = modversion.NewProc("VerQueryValueW")
	proctimeBeginPeriod                                      = modwinmm.NewProc("timeBeginPeriod")
	proctimeEndPeriod                                        = modwinmm.NewProc("timeEndPeriod")
	procWinVerifyTrustEx                                     = modwintrust.NewProc("WinVerifyTrustEx")