return s
		}
	}
	return "errno " + itoa.Itoa(int(e))
}

func (e Errno) Is(target error) bool {
	switch target {
	case oserror.ErrPermission:
		return e == EACCES || e == EPERM
	case oserror.ErrExist:
		return e == EEXIST || e == ENOTEMPTY
	case oserror.ErrNotExist:
		return e == ENOENT
	case errorspkg.ErrUnsupported:
		return e == ENOSYS || e == ENOTSUP || e == EOPNOTSUPP
	}
	return false
}

		// mark respective subtrees manually
		markTree(tree.entries[1])
		markTree(tree.entries[3])
		// correct double-marking of directory itself
		tree.entries[1].mark -= errVisit
		tree.entries[3].mark -= errVisit
		err := walk(tree.name, markFn)
		if err != nil {
			t.Fatalf("expected no error return from Walk, got %s", err)
		}
		if len(errors) != 2 {

			return s
		}
	}
	return "errno " + itoa.Itoa(int(e))
}

func (e Errno) Is(target error) bool {
	switch target {
	case oserror.ErrPermission:
		return e == EACCES || e == EPERM
	case oserror.ErrExist:
		return e == EEXIST || e == ENOTEMPTY
	case oserror.ErrNotExist:
		return e == ENOENT
	case errors.ErrUnsupported:
		return e == ENOSYS
	}
	return false
}

func (e Errno) Temporary() bool {

func NewError(s string) error { return ErrorString(s) }

func (e ErrorString) Is(target error) bool {
	switch target {
	case oserror.ErrPermission:
		return checkErrMessageContent(e, "permission denied")
	case oserror.ErrExist:
		return checkErrMessageContent(e, "exists", "is a directory")
	case oserror.ErrNotExist:
		return checkErrMessageContent(e, "does not exist", "not found",
			"has been removed", "no parent")
	case errors.ErrUnsupported:

			return s
		}
	}
	return "errno " + itoa.Itoa(int(e))
}

func (e Errno) Is(target error) bool {
	switch target {
	case oserror.ErrPermission:
		return e == EACCES || e == EPERM
	case oserror.ErrExist:
		return e == EEXIST || e == ENOTEMPTY
	case oserror.ErrNotExist:
		return e == ENOENT
	case errorspkg.ErrUnsupported:
		return e == ENOSYS || e == ENOTSUP || e == EOPNOTSUPP
	}
	return false
}

)

func (e Errno) Is(target error) bool {
	switch target {
	case oserror.ErrPermission:
		return e == ERROR_ACCESS_DENIED ||
			e == EACCES ||
			e == EPERM
	case oserror.ErrExist:
		return e == ERROR_ALREADY_EXISTS ||
			e == ERROR_DIR_NOT_EMPTY ||
			e == ERROR_FILE_EXISTS ||
			e == EEXIST ||
			e == ENOTEMPTY
	case oserror.ErrNotExist:
		return e == ERROR_FILE_NOT_FOUND ||

		{"(FileMode).IsRegular", Method, 16},
		{"(FileMode).Perm", Method, 16},
		{"(FileMode).String", Method, 16},
		{"(FileMode).Type", Method, 16},
		{"DirEntry", Type, 16},
		{"ErrClosed", Var, 16},
		{"ErrExist", Var, 16},
		{"ErrInvalid", Var, 16},
		{"ErrNotExist", Var, 16},
		{"ErrPermission", Var, 16},
		{"FS", Type, 16},
		{"File", Type, 16},
		{"FileInfo", Type, 16},
		{"FileInfoToDirEntry", Func, 17},