return int64(tv.Sec)*1e9 + int64(tv.Usec)*1000
}

// Getpagesize and Exit are provided by the runtime.

func Getpagesize() int
func Exit(code int)

// runtimeSetenv and runtimeUnsetenv are provided by the runtime.
func runtimeSetenv(k, v string)

	if err != nil {
		return err
	}
	keyp, err := UTF16PtrFromString(key)
	if err != nil {
		return err
	}
	e := SetEnvironmentVariable(keyp, v)
	if e != nil {
		return e
	}
	runtimeSetenv(key, value)
	return nil
}

func Unsetenv(key string) error {
	keyp, err := UTF16PtrFromString(key)
	if err != nil {
		return err
	}
	e := SetEnvironmentVariable(keyp, nil)
	if e != nil {
		return e

	envLock.Lock()
	defer envLock.Unlock()

	i, ok := env[key]
	kv := key + "=" + value
	if ok {
		envs[i] = kv
	} else {
		i = len(envs)
		envs = append(envs, kv)
	}
	env[key] = i
	runtimeSetenv(key, value)
	return nil
}

func Clearenv() {
	envOnce.Do(copyenv) // prevent copyenv in Getenv/Setenv

	envLock.Lock()
	defer envLock.Unlock()

	for k := range env {
		runtimeUnsetenv(k)