What ctypes types are used for WORD and DWORD definitions… here is a solution to the problem.
What ctypes types are used for WORD and DWORD definitions
I have to wrap a DLL written in C into Python. For this, I used the ctypes module.
HOWEVER, SOME C FUNCTIONS USE WORD AND DWORD TYPES. I’ve read some posts about these types, but I can’t understand the exact difference between the two, and what ctypes to choose for them.
FYI, I work on a 64-bit Windows machine.
Solution
ctypes define some Windows constants so you can use the correct type directly without guessing:
>>> from ctypes import wintypes
>>> wintypes. DWORD
<class 'ctypes.c_ulong'>
>>> wintypes. WORD
<class 'ctypes.c_ushort'>
Full list:
>>> dir(wintypes)
['ATOM', 'BOOL', 'BOOLEAN', 'BYTE', 'CHAR', 'COLORREF', 'DOUBLE', 'DWORD', 'FILETIME', 'FLOAT', 'HACCEL', 'HANDLE', 'HBITMAP', 'HB
RUSH', 'HCOLORSPACE', 'HDC', 'HDESK', 'HDWP', 'HENHMETAFILE', 'HFONT', 'HGDIOBJ', 'HGLOBAL', 'HHOOK', 'HICON', 'HINSTANCE', 'HKEY'
, 'HKL', 'HLOCAL', 'HMENU', 'HMETAFILE', 'HMODULE', 'HMONITOR', 'HPALETTE', 'HPEN', 'HRGN', 'HRSRC', 'HSTR', 'HTASK', 'HWINSTA', '
HWND', 'INT', 'LANGID', 'LARGE_INTEGER', 'LCID', 'LCTYPE', 'LGRPID', 'LONG', 'LPARAM', 'LPBOOL', 'LPBYTE', 'LPCOLESTR', 'LPCOLORRE
F', 'LPCSTR', 'LPCVOID', 'LPCWSTR', 'LPDWORD', 'LPFILETIME', 'LPHANDLE', 'LPHKL', 'LPINT', 'LPLONG', 'LPMSG', 'LPOLESTR', 'LPPOINT
', 'LPRECT', 'LPRECTL', 'LPSC_HANDLE', 'LPSIZE', 'LPSIZEL', 'LPSTR', 'LPUINT', 'LPVOID', 'LPWIN32_FIND_DATAA', 'LPWIN32_FIND_DATAW
', 'LPWORD', 'LPWSTR', 'MAX_PATH', 'MSG', 'OLESTR', 'PBOOL', 'PBOOLEAN', 'PBYTE', 'PCHAR', 'PDWORD', 'PFILETIME', 'PFLOAT', 'PHAND
LE', 'PHKEY', 'PINT', 'PLARGE_INTEGER', 'PLCID', 'PLONG', 'PMSG', 'POINT', 'POINTL', 'PPOINT', 'PPOINTL', 'PRECT', 'PRECTL', 'PSHO
RT', 'PSIZE', 'PSIZEL', 'PSMALL_RECT', 'PUINT', 'PULARGE_INTEGER', 'PULONG', 'PUSHORT', 'PWCHAR', 'PWIN32_FIND_DATAA', 'PWIN32_FIN
D_DATAW', 'PWORD', 'RECT', 'RECTL', 'RGB', 'SC_HANDLE', 'SERVICE_STATUS_HANDLE', 'SHORT', 'SIZE', 'SIZEL', 'SMALL_RECT', 'UINT', '
ULARGE_INTEGER', 'ULONG', 'USHORT', 'VARIANT_BOOL', 'WCHAR', 'WIN32_FIND_DATAA', 'WIN32_FIND_DATAW', 'WORD', 'WPARAM', '_COORD', '
_FILETIME', '_LARGE_INTEGER', '_POINTL', '_RECTL', '_SMALL_RECT', '_ULARGE_INTEGER', '__builtins__', '__cached__', '__doc__', '__f
ile__', '__initializing__', '__loader__', '__name__', '__package__', 'ctypes', 'tagMSG', 'tagPOINT', 'tagRECT', 'tagSIZE']
For types that are missing from this list, use a good IDE lookup header with the Go To Definition feature. Using the predefined types above as a guide, it’s often easy to figure these out of those.