This should be a pure refactoring, without user-visible behaviour changes.
Before this change, ctypes uses traditional native C types, usually identified
by [`struct` format characters][struct-chars] when a short (and
identifier-friendly) name is needed:
- `signed char` (`b`) / `unsigned char` (`B`)
- `short` (`h`) / `unsigned short` (`h`)
- `int` (`i`) / `unsigned int` (`i`)
- `long` (`l`) / `unsigned long` (`l`)
- `long long` (`q`) / `unsigned long long` (`q`)
These map to C99 fixed-width types, which this PR switches to: -
- `int8_t`/`uint8_t`
- `int16_t`/`uint16_t`
- `int32_t`/`uint32_t`
- `int64_t`/`uint64_t`
The C standard doesn't guarantee that the “traditional” types must map to the
fixints. But, [`ctypes` currently requires it][swapdefs], so the assumption won't
break anything.
By “map” I mean that the *size* of the types matches. The *alignment*
requirements might not. This needs to be kept in mind but is not an issue in
`ctypes` accessors, which [explicitly handle unaligned memory][memcpy] for the
integer types.
Note that there are 5 “traditional” C type sizes, but 4 fixed-width ones. Two of
the former are functionally identical to one another; which ones they are is
platform-specific (e.g. `int`==`long`==`int32_t`.) This means that one of the
[current][current-impls-1] [implementations][current-impls-2] is redundant on
any given platform.
The fixint types are parametrized by the number of bytes/bits, and one bit for
signedness. This makes it easier to autogenerate code for them or to write
generic macros (though generic API like
[`PyLong_AsNativeBytes`][PyLong_AsNativeBytes] is problematic for performance
reasons -- especially compared to a `memcpy` with compile-time-constant size).
When one has a *different* integer type, determining the corresponding fixint
means a `sizeof` and signedness check. This is easier and more robust than the
current implementations (see [`wchar_t`][sizeof-wchar_t] or
[`_Bool`][sizeof-bool]).
[swapdefs]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L420-L444
[struct-chars]: https://docs.python.org/3/library/struct.html#format-characters
[current-impls-1]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L470-L653
[current-impls-2]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L703-L944
[memcpy]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L613
[PyLong_AsNativeBytes]: https://docs.python.org/3/c-api/long.html#c.PyLong_AsNativeBytes
[sizeof-wchar_t]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L1547-L1555
[sizeof-bool]: https://github.com/python/cpython/blob/v3.13.0/Modules/_ctypes/cfield.c#L1562-L1572
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
- Add a helper to set an error from locale-encoded `char*`
- Use the helper for gdbm & dlerror messages
Co-authored-by: Victor Stinner <vstinner@python.org>
For dlsym(), a return value of NULL does not necessarily indicate
an error [1].
Therefore, to avoid using stale (or NULL) dlerror() values, we must:
1. clear the previous error state by calling dlerror()
2. call dlsym()
3. call dlerror()
If the return value of dlerror() is not NULL, an error occured.
In ctypes we choose to treat a NULL return value from dlsym()
as a "not found" error. This is the same as the fallback
message we use on Windows, Cygwin or when getting/formatting
the error reason fails.
[1]: https://man7.org/linux/man-pages/man3/dlsym.3.html
Signed-off-by: Georgios Alexopoulos <grgalex42@gmail.com>
Signed-off-by: Georgios Alexopoulos <grgalex@ba.uoa.gr>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Co-authored-by: Petr Viktorin <encukou@gmail.com>
Workaround for old libffi versions is added.
Module ctypes now supports C11 double complex only with libffi >= 3.3.0.
Co-authored-by: Sergey B Kirpichev <skirpichev@gmail.com>
- If setting `_fields_` fails, e.g. with AttributeError, don't set the attribute in `__dict__`
- Document the “finalization” behaviour
- Beef up tests: add `getattr`, test Union as well as Structure
- Put common functionality in a common function
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
* Switch PyUnicode_InternInPlace to _PyUnicode_InternMortal, clarify docs
* Document immortality in some functions that take `const char *`
This is PyUnicode_InternFromString;
PyDict_SetItemString, PyObject_SetAttrString;
PyObject_DelAttrString; PyUnicode_InternFromString;
and the PyModule_Add convenience functions.
Always point out a non-immortalizing alternative.
* Don't immortalize user-provided attr names in _ctypes
This amends 6988ff02a5: memory allocation for
stginfo->ffi_type_pointer.elements in PyCSimpleType_init() should be
more generic (perhaps someday fmt->pffi_type->elements will be not a
two-elements array).
It should finally resolve#61103.
Co-authored-by: Victor Stinner <vstinner@python.org>
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Fix warnings when using -Wimplicit-fallthrough compiler flag.
Annotate explicitly "fall through" switch cases with a new
_Py_FALLTHROUGH macro which uses __attribute__((fallthrough)) if
available. Replace "fall through" comments with _Py_FALLTHROUGH.
Add _Py__has_attribute() macro. No longer define __has_attribute()
macro if it's not defined. Move also _Py__has_builtin() at the top
of pyport.h.
Co-Authored-By: Nikita Sobolev <mail@sobolevn.me>
Structure layout, and especially bitfields, sometimes resulted in clearly
wrong behaviour like overlapping fields. This fixes
Co-authored-by: Gregory P. Smith <gps@python.org>
Co-authored-by: Petr Viktorin <encukou@gmail.com>
When the _Py_SINGLETON() is used, Argument Clinic now adds an
explicit "pycore_runtime.h" include to get the macro. Previously, the
macro may or may not be included indirectly by another include.
Add a funciton that inlines PyObject_GetTypeData and skips
type-checking, so it doesn't need access to the CType_Type object.
This will break if the memory layout changes, but should
be an acceptable solution to enable ctypes in subinterpreters in
Python 3.13.
Mark _ctypes as safe for multiple interpreters
Co-authored-by: neonene <53406459+neonene@users.noreply.github.com>
Add _PyType_LookupRef and use incref before setting attribute on type
Makes setting an attribute on a class and signaling type modified atomic
Avoid adding re-entrancy exposing the type cache in an inconsistent state by decrefing after type is updated
This PR adds the ability to enable the GIL if it was disabled at
interpreter startup, and modifies the multi-phase module initialization
path to enable the GIL when loading a module, unless that module's spec
includes a slot indicating it can run safely without the GIL.
PEP 703 called the constant for the slot `Py_mod_gil_not_used`; I went
with `Py_MOD_GIL_NOT_USED` for consistency with gh-104148.
A warning will be issued up to once per interpreter for the first
GIL-using module that is loaded. If `-v` is given, a shorter message
will be printed to stderr every time a GIL-using module is loaded
(including the first one that issues a warning).
Integrates the following ctypes meta tp slot functions:
* `CDataType_traverse()` into `CType_Type_traverse()`.
* `CDataType_clear()` into `CType_Type_clear()`.
* `CDataType_dealloc()` into `CType_Type_dealloc()`.
* `CDataType_repeat()` into `CType_Type_repeat()`.
Before this change, ctypes classes used a custom dict subclass, `StgDict`,
as their `tp_dict`. This acts like a regular dict but also includes extra information
about the type.
This replaces stgdict by `StgInfo`, a C struct on the type, accessed by
`PyObject_GetTypeData()` (PEP-697).
All usage of `StgDict` (mainly variables named `stgdict`, `dict`, `edict` etc.) is
converted to `StgInfo` (named `stginfo`, `info`, `einfo`, etc.).
Where the dict is actually used for class attributes (as a regular PyDict), it's now
called `attrdict`.
This change -- not overriding `tp_dict` -- is made to make me comfortable with
the next part of this PR: moving the initialization logic from `tp_new` to `tp_init`.
The `StgInfo` is set up in `__init__` of each class, with a guard that prevents
calling `__init__` more than once. Note that abstract classes (like `Array` or
`Structure`) are created using `PyType_FromMetaclass` and do not have
`__init__` called.
Previously, this was done in `__new__`, which also wasn't called for abstract
classes.
Since `__init__` can be called from Python code or skipped, there is a tested
guard to ensure `StgInfo` is initialized exactly once before it's used.
Co-authored-by: neonene <53406459+neonene@users.noreply.github.com>
Co-authored-by: Erlend E. Aasland <erlend.aasland@protonmail.com>
The length field of StgDictObject for Structure class contains now
the total number of items in ffi_type_pointer.elements (excluding
the trailing null).
The old behavior of using the number of elements in the parent class can
cause the array to be truncated when it is copied, especially when there
are multiple layers of subclassing.
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Set MAX_STRUCT_SIZE to 32 in stgdict.c when on Arm platforms.
This because on Arm platforms structs with at most 4 elements of any
floating point type values can be passed through registers. If the type
is double the maximum size of the struct is 32 bytes.
On x86-64 Linux, it's maximum 16 bytes hence we need to differentiate.
Peter Bierma