Repository navigation
Annotation-based decorator for ctypes function pointers #153903
Description
Feature or enhancement
Proposal:
The idea is to add a decorator that extracts type annotations and a name for a function signature, and then use that information to generate argtypes and restype for a _CFuncPtr object. For example:
@wrap_dll_function(ctypes.pythonapi)
def PyObject_GetAttrString(op: ctypes.py_object, attr: ctypes.c_char_p) -> ctypes.py_object:
...See #104533 for prior work.
Has this already been discussed elsewhere?
I have already discussed this feature proposal on Discourse
Links to previous discussion of this feature:
https://discuss.python.org/t/annotation-based-sugar-for-ctypes/26579
Linked PRs
- gh-153903: Add a
ctypesdecorator for generating function pointers using annotations #153904 - gh-153903: Use
@ctypes.util.wrap_dll_function()with pythonapi #154030 - gh-153903: Fix ctypes wrap_dll_function() with string annotations #154042
- gh-153903: Use
@ctypes.util.wrap_dll_function()#154122 - gh-153903: wrap_dll_function: copy doc, etc from wrapped stub #154495
Metadata
Metadata
Assignees
Projects
- Status
Activity
gh-153903: Add a `ctypes` decorator for generating function pointers …
pythongh-153903: Fix ctypes wrap_dll_function() with string annotations
gh-153903: Fix ctypes wrap_dll_function() with string annotations (#1…
gh-153903: Use `@ctypes.util.wrap_dll_function()` with pythonapi (#15…
gh-153903: Use `@ctypes.util.wrap_dll_function()` (#154122)
WardBrian commentedon Jul 21, 2026
It would also be nice if this propagated doc comments, which I don't believe gh-153904 does
ZeroIntensity commentedon Jul 21, 2026
Do you have a compelling use case for that?
WardBrian commentedon Jul 21, 2026
It would just be a nice-to-have if things like
help()in the REPL (or?in ipython) reproduced the docstring if one was provided on the stub. I think this could also be used by tools like sphinx. Whenever I write a decorator I tend to usefunctools.wraps, but I think the only relevant thing here is actually the.__doc__member.Currently, if you use the example in the docs:
help(PyObject_GetAttrString)would print the help forctypes._FuncPtr. It would be nice if a user could write something likeAnd have that string not just be swallowed/ignored
ZeroIntensity commentedon Jul 21, 2026
Seems reasonable. Would you like to submit a PR?
WardBrian commentedon Jul 21, 2026
Happy to!
gh-153903: Copy docstrings and other metadata in `ctypes.util.wrap_dl…
pythongh-153903: Copy docstrings and other metadata in `ctypes.util.w…