我正在尝试为使用 gobject 的结构创建一个 ctypes 包装器。
结构定义如下:
struct GstMetaStruc
{
GstMeta meta;
GstStructure* structure;
};
GstMeta 有一个现有的内省(introspection)包装器,可以让我访问基本元对象。
我目前的错误做法是这样的:
import ctypes
import gi
gi.require_version("Gst", "1.0")
from gi.repository import Gst
class TcamMeta(ctypes.Structure):
"""
"""
_fields_ = [("meta", Gst.Meta),
("structure", ctypes.POINTER(Gst.Structure))]
是否可以将 ctype 定义与现有的 python 包装类混合使用?
是否有更好的方法来为派生类型定义 Python 类?
最佳答案
[Python 3.Docs]: ctypes - Structures and unions状态(强调是我的):
Structures and unions must derive from the Structure and Union base classes which are defined in the ctypes module. Each subclass must define a _fields_ attribute. _fields_ must be a list of 2-tuples, containing a field name and a field type.
The field type must be a ctypes type like c_int, or any other derived ctypes type: structure, union, array, pointer.
_fields_ 成员被实现为描述符,这意味着它们是“特殊的”(与常规类成员相比)。因此,在声明结构时会执行一些检查。
>>> import ctypes as ct >>> >>> class A: pass ... >>> class Stru0(ct.Structure): pass ... >>> class Stru1(ct.Structure): _fields_ = [("c", Stru0)] ... >>> class Stru1(ct.Structure): _fields_ = [("c", ct.c_float)] ... >>> class Stru1(ct.Structure): _fields_ = [("c", int)] ... Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: second item in _fields_ tuple (index 0) must be a C type >>> class Stru1(ct.Structure): _fields_ = [("c", A)] ... Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: second item in _fields_ tuple (index 0) must be a C type
因此,如果您没有遇到TypeError,您可能OK。但是简单地看一下 PyGObject 示例,您不应该遇到需要这样做的情况。
关于python - 在 _fields_ 中混合 ctypes 和 python 类,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/61265051/