//sys	ExtattrSetFile(file string, attrnamespace int, attrname string, data uintptr, nbytes int) (ret int, err error)
//sys	ExtattrDeleteFile(file string, attrnamespace int, attrname string) (err error)
//sys	ExtattrListFile(file string, attrnamespace int, data uintptr, nbytes int) (ret int, err error)
//sys	ExtattrGetLink(link string, attrnamespace int, attrname string, data uintptr, nbytes int) (ret int, err error)

	// Read a count.
	nbytes, _, err := decodeUintReader(dec.r, dec.countBuf)
	if err != nil {
		dec.err = err
		return false
	}
	if nbytes >= tooBig {
		dec.err = errBadCount
		return false
	}
	dec.readMessage(int(nbytes))
	return dec.err == nil
}

// readMessage reads the next nbytes bytes from the input.
func (dec *Decoder) readMessage(nbytes int) {
	if dec.buf.Len() != 0 {

	pr, _ := io.Pipe()
	tests := []struct {
		r    io.Reader
		want bool
	}{
		{pr, false},

		{bytes.NewReader(nil), true},
		{bytes.NewBuffer(nil), true},
		{strings.NewReader(""), true},

		{io.NopCloser(pr), false},

		{io.NopCloser(bytes.NewReader(nil)), true},
		{io.NopCloser(bytes.NewBuffer(nil)), true},
		{io.NopCloser(strings.NewReader("")), true},
	}
	for i, tt := range tests {

func (s *formatState) parseIndex() bool {
	if s.nbytes == len(s.format) || s.format[s.nbytes] != '[' {
		return true
	}
	// Argument index present.
	s.nbytes++ // skip '['
	start := s.nbytes
	s.scanNum()
	ok := true
	if s.nbytes == len(s.format) || s.nbytes == start || s.format[s.nbytes] != ']' {
		ok = false // syntax error is either missing "]" or invalid index.
		s.nbytes = strings.Index(s.format[start:], "]")

	SYS_EXTATTR_LIST_FILE        = 438 // { ssize_t extattr_list_file(const char *path, int attrnamespace, void *data, size_t nbytes); }
	SYS_EXTATTR_LIST_LINK        = 439 // { ssize_t extattr_list_link(const char *path, int attrnamespace, void *data, size_t nbytes); }

	SYS_EXTATTR_LIST_FILE        = 438 // { ssize_t extattr_list_file(const char *path, int attrnamespace, void *data, size_t nbytes); }
	SYS_EXTATTR_LIST_LINK        = 439 // { ssize_t extattr_list_link(const char *path, int attrnamespace, void *data, size_t nbytes); }

//sys	ExtattrSetFile(file string, attrnamespace int, attrname string, data uintptr, nbytes int) (ret int, err error)
//sys	ExtattrDeleteFile(file string, attrnamespace int, attrname string) (err error)
//sys	ExtattrListFile(file string, attrnamespace int, data uintptr, nbytes int) (ret int, err error)
//sys	ExtattrGetLink(link string, attrnamespace int, attrname string, data uintptr, nbytes int) (ret int, err error)

	if !Equal(buf.Bytes(), b) {
		t.Fatalf("incorrect result from WriteRune: %q not %q", buf.Bytes(), b)
	}

	p := make([]byte, utf8.UTFMax)
	// Read it back with ReadRune
	for r := rune(0); r < NRune; r++ {
		size := utf8.EncodeRune(p, r)
		nr, nbytes, err := buf.ReadRune()
		if nr != r || nbytes != size || err != nil {
			t.Fatalf("ReadRune(%U) got %U,%d not %U,%d (err=%s)", r, nr, nbytes, r, size, err)
		}

	SYS_EXTATTR_GET_LINK     = 368 // { ssize_t|sys||extattr_get_link(const char *path, int attrnamespace, const char *attrname, void *data, size_t nbytes); }
	SYS_EXTATTR_DELETE_LINK  = 369 // { int|sys||extattr_delete_link(const char *path, int attrnamespace, const char *attrname); }
	SYS_EXTATTR_LIST_FD      = 370 // { ssize_t|sys||extattr_list_fd(int fd, int attrnamespace, void *data, size_t nbytes); }

	SYS_EXTATTR_GET_LINK     = 368 // { ssize_t|sys||extattr_get_link(const char *path, int attrnamespace, const char *attrname, void *data, size_t nbytes); }
	SYS_EXTATTR_DELETE_LINK  = 369 // { int|sys||extattr_delete_link(const char *path, int attrnamespace, const char *attrname); }
	SYS_EXTATTR_LIST_FD      = 370 // { ssize_t|sys||extattr_list_fd(int fd, int attrnamespace, void *data, size_t nbytes); }