ctypes中使用WindowFromPoint

ctypes是一大利器，为Python调用c库函数、dll使用等提供了极大的便利。 但是使用ctypes下的函数遇到一些复杂的数据类型传参时怎么使用对接的数据类型呢。 很简单的比如使用ctypes.windll.user32.WindowFromPoint(POINT)函数。这个POINT类型Python中是没有的，而且ctypes下没有此类型。如何传参调用呢。

经过查阅官方文档，终于找到了最终解决方案。

直接使用报错如下

ctypes.ArgumentError: argument 1: <class 'TypeError'>: Don't know how to convert parameter 1

解决方案

import ctypes class POINT(ctypes.Structure): _fields_ = [("x", ctypes.c_int), ("y", ctypes.c_int)] op = ctypes.windll.user32 print(op.WindowFromPoint(POINT(30, 40)))

官方文档说明

16.16.2.8. Structured data types class ctypes.Union(*args, **kw) Abstract base class for unions in native byte order. class ctypes.BigEndianStructure(*args, **kw) Abstract base class for structures in big endian byte order. class ctypes.LittleEndianStructure(*args, **kw) Abstract base class for structures in little endian byte order. Structures with non-native byte order cannot contain pointer type fields, or any other data types containing pointer type fields. class ctypes.Structure(*args, **kw) Abstract base class for structures in native byte order. Concrete structure and union types must be created by subclassing one of these types, and at least define a _fields_ class variable. ctypes will create descriptors which allow reading and writing the fields by direct attribute accesses. These are the _fields_ A sequence defining the structure fields. The items must be 2-tuples or 3-tuples. The first item is the name of the field, the second item specifies the type of the field; it can be any ctypes data type. For integer type fields like c_int, a third optional item can be given. It must be a small positive integer defining the bit width of the field. Field names must be unique within one structure or union. This is not checked, only one field can be accessed when names are repeated. It is possible to define the _fields_ class variable after the class statement that defines the Structure subclass, this allows creating data types that directly or indirectly reference themselves: class List(Structure): pass List._fields_ = [("pnext", POINTER(List)), ... ] The _fields_ class variable must, however, be defined before the type is first used (an instance is created, sizeof() is called on it, and so on). Later assignments to the _fields_ class variable will raise an AttributeError. It is possible to defined sub-subclasses of structure types, they inherit the fields of the base class plus the _fields_ defined in the sub-subclass, if any. _pack_ An optional small integer that allows overriding the alignment of structure fields in the instance. _pack_ must already be defined when _fields_ is assigned, otherwise it will have no effect. _anonymous_ An optional sequence that lists the names of unnamed (anonymous) fields. _anonymous_ must be already defined when _fields_ is assigned, otherwise it will have no effect. The fields listed in this variable must be structure or union type fields. ctypes will create descriptors in the structure type that allows accessing the nested fields directly, without the need to create the structure or union field. Here is an example type (Windows): class _U(Union): _fields_ = [("lptdesc", POINTER(TYPEDESC)), ("lpadesc", POINTER(ARRAYDESC)), ("hreftype", HREFTYPE)] class TYPEDESC(Structure): _anonymous_ = ("u",) _fields_ = [("u", _U), ("vt", VARTYPE)] The TYPEDESC structure describes a COM data type, the vt field specifies which one of the union fields is valid. Since the u field is defined as anonymous field, it is now possible to access the members directly off the TYPEDESC instance. td.lptdesc and td.u.lptdesc are equivalent, but the former is faster since it does not need to create a temporary union instance: td = TYPEDESC() td.vt = VT_PTR td.lptdesc = POINTER(some_type) td.u.lptdesc = POINTER(some_type) It is possible to defined sub-subclasses of structures, they inherit the fields of the base class. If the subclass definition has a separate _fields_ variable, the fields specified in this are appended to the fields of the base class. Structure and union constructors accept both positional and keyword arguments. Positional arguments are used to initialize member fields in the same order as they are appear in _fields_. Keyword arguments in the constructor are interpreted as attribute assignments, so they will initialize _fields_ with the same name, or create new attributes for names not present in _fields_.