ctypes exports the cdll, and on Windows also windll and
oledll objects to load dynamic link libraries.
You load libraries by accessing them as attributes of these objects.
cdll loads libraries which export functions using the standard
cdecl calling convention, while windll libraries call
functions using the
stdcall calling convention. oledll also
stdcall calling convention, and assumes the functions
return a Windows HRESULT error code. The error code is used to
automatically raise WindowsError Python exceptions when the
function call fails.
Here are some examples for Windows, note that
msvcrt is the MS
standard C library containing most standard C functions, and uses the
cdecl calling convention:
>>> from ctypes import * >>> print windll.kernel32 # doctest: +WINDOWS <WinDLL 'kernel32', handle ... at ...> >>> print cdll.msvcrt # doctest: +WINDOWS <CDLL 'msvcrt', handle ... at ...> >>> libc = cdll.msvcrt # doctest: +WINDOWS >>>
Windows appends the usual '.dll' file suffix automatically.
On Linux, it is required to specify the filename including the extension to load a library, so attribute access does not work. Either the LoadLibrary method of the dll loaders should be used, or you should load the library by creating an instance of CDLL by calling the constructor:
>>> cdll.LoadLibrary("libc.so.6") # doctest: +LINUX <CDLL 'libc.so.6', handle ... at ...> >>> libc = CDLL("libc.so.6") # doctest: +LINUX >>> libc # doctest: +LINUX <CDLL 'libc.so.6', handle ... at ...> >>>
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