auto
 ?÷        else:
            prnt('  Py_INCREF(Py_None);')
            prnt('  return Py_None;')
        prnt('}')
        prnt()

    def _generate_cpy_function_method(self, tp, name):
        if tp.ellipsis:
            return
        numargs = len(tp.args)
        if numargs == 0:
            meth = 'METH_NOARGS'
        elif numargs == 1:
            meth = 'METH_O'
        else:
            meth = 'METH_VARARGS'
        self._prnt('  {"%s", _cffi_f_%s, %s, NULL},' % (name, name, meth))

    _loading_cpy_function = _loaded_noop

    def _loaded_cpy_function(self, tp, name, module, library):
        if tp.ellipsis:
            return
        func = getattr(module, name)
        setattr(library, name, func)
        self._types_of_builtin_functions[func] = tp

    # ----------
    # named structs

    _generate_cpy_struct_collecttype = _generate_nothing
    def _generate_cpy_struct_decl(self, tp, name):
        assert name == tp.name
        self._generate_struct_or_union_decl(tp, 'struct', name)
    def _generate_cpy_struct_method(self, tp, name):
        self._generate_struct_or_union_method(tp, 'struct', name)
    def _loading_cpy_struct(self, tp, name, module):
        self._loading_struct_or_union(tp, 'struct', name, module)
    def _loaded_cpy_struct(self, tp, name, module, **kwds):
        self._loaded_struct_or_union(tp)

    _generate_cpy_union_collecttype = _generate_nothing
    def _generate_cpy_union_decl(self, tp, name):
        assert name == tp.name
        self._generate_struct_or_union_decl(tp, 'union', name)
    def _generate_cpy_union_method(self, tp, name):
        self._generate_struct_or_union_method(tp, 'union', name)
    def _loading_cpy_union(self, tp, name, module):
        self._loading_struct_or_union(tp, 'union', name, module)
    def _loaded_cpy_union(self, tp, name, module, **kwds):
        self._loaded_struct_or_union(tp)

    def _generate_struct_or_union_decl(self, tp, prefix, name):
        if tp.fldnames is None:
            return     # nothing to do with opaque structs
        checkfuncname = '_cffi_check_%s_%s' % (prefix, name)
        layoutfuncname = '_cffi_layout_%s_%s' % (prefix, name)
        cname = ('%s %s' % (prefix, name)).strip()
        #
        prnt = self._prnt
        prnt('static void %s(%s *p)' % (checkfuncname, cname))
        prnt('{')
        prnt('  /* only to generate compile-time warnings or errors */')
        prnt('  (void)p;')
        for fname, ftype, fbitsize, fqual in tp.enumfields():
            if (isinstance(ftype, model.PrimitiveType)
                and ftype.is_integer_type()) or fbitsize >= 0:
                # accept all integers, but complain on float or double
                prnt('  (void)((p->%s) << 1);' % fname)
            else:
                # only accept exactly the type declared.
                try:
                    prnt('  { %s = &p->%s; (void)tmp; }' % (
                        ftype.get_c_name('*tmp', 'field %r'%fname, quals=fqual),
                        fname))
                except ffiplatform.VerificationError as e:
                    prnt('  /* %s */' % str(e))   # cannot verify it, ignore
        prnt('}')
        prnt('static PyObject *')
        prnt('%s(PyObject *self, PyObject *noarg)' % (layoutfuncname,))
        prnt('{')
        prnt('  struct _cffi_aligncheck { char x; %s y; };' % cname)
        prnt('  static Py_ssize_t nums[] = {')
        prnt('    sizeof(%s),' % cname)
        prnt('    offsetof(struct _cffi_aligncheck, y),')
        for fname, ftype, fbitsize, fqual in tp.enumfields():
            if fbitsize >= 0:
                continue      # xxx ignore fbitsize for now
            prnt('    offsetof(%s, %s),' % (cname, fname))
            if isinstance(ftype, model.ArrayType) and ftype.length is None:
                prnt('    0,  /* %s */' % ftype._get_c_name())
            else:
                prnt('    sizeof(((%s *)0)->%s),' % (cname, fname))
        prnt('    -1')
        prnt('  };')
        prnt('  (void)self; /* unused */')
        prnt('  (void)noarg; /* unused */')
        prnt('  ret