Error in creating an instance of structure.

[prashant-saxena]

Hello,
struct in header file

typedef struct WGPURequestAdapterOptions {
    WGPUChainedStruct const * nextInChain;
    WGPUSurface compatibleSurface; // nullable
    WGPUPowerPreference powerPreference;
    bool forceFallbackAdapter;
} WGPURequestAdapterOptions;

I have added a print statement in ctypes.py

    def _get_type(self, typ, pointers=True):
        """Return a ctype object representing the named type.

        If pointers is True, the class returned includes all pointer/array
        specs provided. Otherwise, the class returned is just the base type
        with no pointers.

        """
        print(typ)

Loading the lib using parser object with prefix=['WGPU','wgpu'] options.
and the error is

Type('struct WGPURequestAdapterOptions')
Type('WGPUChainedStruct', '*', type_quals=(('const',), ()))
Type('struct WGPUChainedStruct', '*', type_quals=(('const',), ()))
Type('WGPUSType')
Type('WGPUSurface')
Type('WGPUPowerPreference')
Type('bool')
Traceback (most recent call last):
  File "E:\projects\webgpu\python\parselib.py", line 1, in <module>
    import webgpu as wgpu
  File "E:\projects\webgpu\python\webgpu.py", line 24, in <module>
    r = clib.WGPURequestAdapterOptions()
  File "E:\projects\webgpu\python\venv\lib\site-packages\pyclibrary\c_library.py", line 225, in __getattr__
    obj = self(k, n)
  File "E:\projects\webgpu\python\venv\lib\site-packages\pyclibrary\c_library.py", line 205, in __call__
    self._objs_[typ][name] = self._make_obj_(typ, name)
  File "E:\projects\webgpu\python\venv\lib\site-packages\pyclibrary\c_library.py", line 270, in _make_obj_
    return self._get_type(obj)
  File "E:\projects\webgpu\python\venv\lib\site-packages\pyclibrary\backends\ctypes.py", line 165, in _get_type
    cls = self._get_struct('structs',
  File "E:\projects\webgpu\python\venv\lib\site-packages\pyclibrary\backends\ctypes.py", line 304, in _get_struct
    s._fields_ = [(m[0], self._get_type(m[1])) if m[2] is None else
  File "E:\projects\webgpu\python\venv\lib\site-packages\pyclibrary\backends\ctypes.py", line 304, in <listcomp>
    s._fields_ = [(m[0], self._get_type(m[1])) if m[2] is None else
  File "E:\projects\webgpu\python\venv\lib\site-packages\pyclibrary\backends\ctypes.py", line 177, in _get_type
    raise KeyError("Can't find base type for {}".format(typ))
KeyError: "Can't find base type for ['bool']"

[MatthieuDartiailh]

From the top of my head bool is not a standard C type. So you need to add a definition and you can use the bool present in ctypes to represent it.

[prashant-saxena]

Hello,
I did a minor change in _get_type method in ctypes.py:

...
elif typ[0] == 'bool':
    cls = c_bool
else:
    raise KeyError("Can't find base type for {}".format(typ))
...

and it's working. Are you suggesting the same? If not then could you please explain further.

[MatthieuDartiailh]

I am a bit confused because bool is present in the _types_ populated in https://github.com/MatthieuDartiailh/pyclibrary/blob/main/pyclibrary/backends/ctypes.py#L367C1-L367C1

Could you inspect this attribute and post the version you are using ?

[prashant-saxena]

I am using version 0.2.1

[MatthieuDartiailh]

So it is the last version which is up to date with main. So can you check the content of the _types_ attribute on the library object ?

[prashant-saxena]

I don't see this types attribute. Neither on parser nor on the library object. Here is the output:

print(dir(parser))
['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_format_parsed_file', '_init', 'abstract_declarator', 'add_def', 'build_parser', 'cache_version', 'compile_fn_macro', 'compiled_types', 'current_file', 'data_list', 'decl_list', 'declarator', 'declarator_list', 'defs', 'enum_decl', 'enum_type', 'eval', 'eval_expr', 'eval_preprocessor_expr', 'eval_type', 'expand_fn_macro', 'expand_macros', 'file_defs', 'file_order', 'files', 'find', 'find_headers', 'find_text', 'function_decl', 'import_dict', 'init_opts', 'is_fund_type', 'load_cache', 'load_file', 'pack_list', 'packing_at', 'parse_defs', 'parser', 'pp_define', 'preprocess', 'print_all', 'process_all', 'process_declarator', 'process_enum', 'process_function', 'process_macro_defn', 'process_struct', 'process_type', 'process_typedef', 'process_variable', 'rem_def', 'remove_comments', 'struct_decl', 'struct_member', 'struct_type', 'type_decl', 'type_spec', 'typeless_function_decl', 'variable_decl', 'write_cache']