func TestReadNonblockingFd(t *testing.T) {
	switch runtime.GOOS {
	case "windows":
		t.Skip("Windows doesn't support SetNonblock")
	}
	if os.Getenv("GO_WANT_READ_NONBLOCKING_FD") == "1" {
		fd := syscallDescriptor(os.Stdin.Fd())
		syscall.SetNonblock(fd, true)
		defer syscall.SetNonblock(fd, false)
		_, err := os.Stdin.Read(make([]byte, 1))
		if err != nil {

	// runtime supports non-blocking stdio, the Go runtime is able to
	// use the WASI net poller to poll for read/write readiness and is
	// able to schedule goroutines while waiting.
	SetNonblock(0, true)
	SetNonblock(1, true)
	SetNonblock(2, true)
}

type uintptr32 = uint32
type size = uint32
type fdflags = uint32
type filesize = uint64
type filetype = uint8
type lookupflags = uint32
type oflags = uint32

		t.Fatalf("pipe: %v", err)
	}
	defer syscall.Close(p[1])

	// Set the read-side to non-blocking.
	if !blocking {
		if err := syscall.SetNonblock(p[0], true); err != nil {
			syscall.Close(p[0])
			t.Fatalf("SetNonblock: %v", err)
		}
	}
	// Convert it to a file.
	file := NewFile(uintptr(p[0]), "notapipe")
	if file == nil {
		syscall.Close(p[0])

		// non-blocking mode.
		if nonBlocking {
			// See the comments on net_newUnixFile.
			if kind == kindSock {
				f.nonblock = true // tell Fd to return blocking descriptor
			}
		} else if err := syscall.SetNonblock(fd, true); err == nil {
			f.nonblock = true
			clearNonBlock = true
		} else {
			pollable = false
		}
	}

	// An error here indicates a failure to register

		}
		b = utf16.AppendRune(b, 0)
	}
	b = utf16.AppendRune(b, 0)
	return b, nil
}

func CloseOnExec(fd Handle) {
	SetHandleInformation(Handle(fd), HANDLE_FLAG_INHERIT, 0)
}

func SetNonblock(fd Handle, nonblocking bool) (err error) {
	return nil
}

// FullPath retrieves the full path of the specified file.
func FullPath(name string) (path string, err error) {
	p, err := UTF16PtrFromString(name)

	// buffer is somehow full we will not block in the signal handler.
	// Leave the read end of the pipe blocking so that we will block
	// in sigNoteSleep.
	setNonblock(sigNoteWrite)
}

// sigNoteWakeup wakes up a thread sleeping on a note created by sigNoteSetup.
func sigNoteWakeup(*note) {
	var b byte
	write(uintptr(sigNoteWrite), unsafe.Pointer(&b), 1)
}

	if err == nil {
		fd[0] = int(fdx[0])
		fd[1] = int(fdx[1])
	}
	return
}

var ioSync int64

func CloseOnExec(fd int) { fcntl(fd, F_SETFD, FD_CLOEXEC) }

func SetNonblock(fd int, nonblocking bool) (err error) {
	flag, err := fcntl(fd, F_GETFL, 0)
	if err != nil {
		return err
	}
	if (flag&O_NONBLOCK != 0) == nonblocking {
		return nil
	}
	if nonblocking {

	// Atomic store so that concurrent calls to SetBlocking
	// do not cause a race condition. isBlocking only ever goes
	// from 0 to 1 so there is no real race here.
	atomic.StoreUint32(&fd.isBlocking, 1)
	return syscall.SetNonblock(fd.Sysfd, false)
}

// Darwin and FreeBSD can't read or write 2GB+ files at a time,
// even on 64-bit systems.
// The same is true of socket implementations on many systems.

	return ret
}
func pthread_cond_signal_trampoline()

// Not used on Darwin, but must be defined.
func exitThread(wait *atomic.Uint32) {
	throw("exitThread")
}

//go:nosplit
func setNonblock(fd int32) {
	flags, _ := fcntl(fd, _F_GETFL, 0)
	if flags != -1 {
		fcntl(fd, _F_SETFL, flags|_O_NONBLOCK)
	}
}

func issetugid() int32 {