if wantSock != gotSock {
		t.Fatalf("SupportSockNonblockCloexec, got %t; want %t", gotSock, wantSock)
	}

	// Test that SupportAccept4 returns true if accept4 is available.
	for {
		_, _, err = syscall.Accept4(0, syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC)
		if err != syscall.EINTR {
			break
		}
	}
	wantAccept4 := err != syscall.ENOSYS
	gotAccept4 := unix.SupportAccept4()

//go:cgo_import_dynamic libc_preadv preadv "libc.so"
//go:cgo_import_dynamic libc_writev writev "libc.so"
//go:cgo_import_dynamic libc_pwritev pwritev "libc.so"
//go:cgo_import_dynamic libc_accept4 accept4 "libsocket.so"

//go:linkname procreadv libc_readv
//go:linkname procpreadv libc_preadv
//go:linkname procwritev libc_writev
//go:linkname procpwritev libc_pwritev
//go:linkname procaccept4 libc_accept4

var (

	if err == nil {
		p[0] = int(pp[0])
		p[1] = int(pp[1])
	}
	return err
}

//sys	accept4(fd int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (nfd int, err error)

func Accept4(fd, flags int) (nfd int, sa Sockaddr, err error) {
	var rsa RawSockaddrAny
	var len _Socklen = SizeofSockaddrAny
	nfd, err = accept4(fd, &rsa, &len, flags)
	if err != nil {
		return
	}
	if len > SizeofSockaddrAny {

pkg runtime/trace, type Task struct
pkg syscall (netbsd-386), func Accept4(int, int) (int, Sockaddr, error)
pkg syscall (netbsd-386), func Pipe2([]int, int) error
pkg syscall (netbsd-386-cgo), func Accept4(int, int) (int, Sockaddr, error)
pkg syscall (netbsd-386-cgo), func Pipe2([]int, int) error
pkg syscall (netbsd-amd64), func Accept4(int, int) (int, Sockaddr, error)
pkg syscall (netbsd-amd64), func Pipe2([]int, int) error

	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), unsafe.Sizeof(*mreq))
}

func Accept4(fd, flags int) (nfd int, sa Sockaddr, err error) {
	var rsa RawSockaddrAny
	var len _Socklen = SizeofSockaddrAny
	nfd, err = accept4(fd, &rsa, &len, flags)
	if err != nil {
		return
	}
	if len > SizeofSockaddrAny {
		panic("RawSockaddrAny too small")
	}

func pwrite(fd int, p []byte, offset int64) (n int, err error) {
	return extpwrite(fd, p, 0, offset)
}

func Accept4(fd, flags int) (nfd int, sa Sockaddr, err error) {
	var rsa RawSockaddrAny
	var len _Socklen = SizeofSockaddrAny
	nfd, err = accept4(fd, &rsa, &len, flags)
	if err != nil {
		return
	}
	if len > SizeofSockaddrAny {
		panic("RawSockaddrAny too small")
	}

func pwrite(fd int, p []byte, offset int64) (n int, err error) {
	return extpwrite(fd, p, 0, offset)
}

func Accept4(fd, flags int) (nfd int, sa Sockaddr, err error) {
	var rsa RawSockaddrAny
	var len _Socklen = SizeofSockaddrAny
	nfd, err = accept4(fd, &rsa, &len, flags)
	if err != nil {
		return
	}
	if len > SizeofSockaddrAny {
		panic("RawSockaddrAny too small")
	}

	if err == nil {
		p[0] = int(pp[0])
		p[1] = int(pp[1])
	}
	return err
}

//sys   accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int, err error) = libsocket.accept4

func Accept4(fd int, flags int) (int, Sockaddr, error) {
	var rsa RawSockaddrAny
	var addrlen _Socklen = SizeofSockaddrAny
	nfd, err := accept4(fd, &rsa, &addrlen, flags)
	if err != nil {
		return 0, nil, err
	}

	FilterSocket        FilterType = iota // for Socket
	FilterConnect                         // for Connect or ConnectEx
	FilterListen                          // for Listen
	FilterAccept                          // for Accept, Accept4 or AcceptEx
	FilterGetsockoptInt                   // for GetsockoptInt
	FilterClose                           // for Close or Closesocket
)

// A Filter represents a socket system call filter.
//

	x := new(Xucred)
	vallen := _Socklen(SizeofXucred)
	err := getsockopt(fd, level, opt, unsafe.Pointer(x), &vallen)
	return x, err
}

func Accept4(fd, flags int) (nfd int, sa Sockaddr, err error) {
	var rsa RawSockaddrAny
	var len _Socklen = SizeofSockaddrAny
	nfd, err = accept4(fd, &rsa, &len, flags)
	if err != nil {
		return
	}
	if len > SizeofSockaddrAny {
		panic("RawSockaddrAny too small")
	}