Calling SetupDiGetClassDevsW function如何输入参数

Question

我正在使用Python中的SetupDiGetClassDevsW函数，但我不知道如何输入参数Flags = DIGCF_PRESENT出错，NameError: name 'DIGCF_PRESENT' is not defined出错请问我该怎么办?

https://learn.microsoft.com/zh-tw/windows/win32/api/setupapi/nf-setupapi-setupdigetclassdevsw?redirectedfrom=MSDN

import ctypes as ct
from ctypes import wintypes as w
SetupAPI = ct.WinDLL('SetupAPI')
SetupAPI.SetupDiGetClassDevsW.argtypes = w.CHAR,w.PWCHAR,w.HWND,w.DWORD
SetupAPI.SetupDiGetClassDevsW.restype = w.HANDLE
ClassGuid = None
Enumerator = None
hwndParent = None
Flags = DIGCF_PRESENT
Handle = SetupAPI.SetupDiGetClassDevsW(ClassGuid,
Enumerator,
hwndParent,
Flags)

Update - 2

更新后的代码如下，打印HANDLE得到18446744073709551615对吗?期望获得设备信息。

import ctypes as ct
from ctypes import wintypes as w
SetupAPI = ct.WinDLL('SetupAPI')
SetupAPI.SetupDiGetClassDevsW.argtypes w.LPVOID,w.PWCHAR,w.HWND,w.DWORD
SetupAPI.SetupDiGetClassDevsW.restype = w.HANDLE
DIGCF_DEFAULT         =  0x00000001  
DIGCF_PRESENT         =  0x00000002
DIGCF_ALLCLASSES      =  0x00000004
DIGCF_PROFILE         =  0x00000008
DIGCF_DEVICEINTERFACE =  0x00000010
ClassGuid = None
Enumerator = None
hwndParent = None
Flags = DIGCF_PRESENT
Handle = SetupAPI.SetupDiGetClassDevsW(ClassGuid,
Enumerator,
hwndParent,
Flags)
print(Handle)

Answer 1

查看SetupApi.h:

//
// Flags controlling what is included in the device information set built
// by SetupDiGetClassDevs
//
#define DIGCF_DEFAULT           0x00000001  // only valid with DIGCF_DEVICEINTERFACE
#define DIGCF_PRESENT           0x00000002
#define DIGCF_ALLCLASSES        0x00000004
#define DIGCF_PROFILE           0x00000008
#define DIGCF_DEVICEINTERFACE   0x00000010

你可以在Python中定义常量:

DIGCF_DEFAULT         =  0x00000001  # only valid with DIGCF_DEVICEINTERFACE
DIGCF_PRESENT         =  0x00000002
DIGCF_ALLCLASSES      =  0x00000004
DIGCF_PROFILE         =  0x00000008
DIGCF_DEVICEINTERFACE =  0x00000010

还请注意，SetupDiGetClassDevsW的第一个参数是GUID*，而不是CHAR，所以如果只传递None,.argtypes应该至少是w.LPVOID。

还要查看文档中的示例。下面返回一个有效句柄:

import ctypes as ct
from ctypes import wintypes as w
SetupAPI = ct.WinDLL('SetupAPI')
SetupAPI.SetupDiGetClassDevsW.argtypes = w.LPVOID,w.PWCHAR,w.HWND,w.DWORD
SetupAPI.SetupDiGetClassDevsW.restype = w.HANDLE
DIGCF_DEFAULT         =  0x00000001  
DIGCF_PRESENT         =  0x00000002
DIGCF_ALLCLASSES      =  0x00000004
DIGCF_PROFILE         =  0x00000008
DIGCF_DEVICEINTERFACE =  0x00000010
ClassGuid = None
Enumerator = None
hwndParent = None
Flags = DIGCF_PRESENT | DIGCF_ALLCLASSES
Handle = SetupAPI.SetupDiGetClassDevsW(ClassGuid,
Enumerator,
hwndParent,
Flags)
print(hex(Handle))

输出:

0x1e4258bcb50