Help: 64bit python call c and got OSError: exception: access violation writing 0xFFFFFFFF99222A60

[Jason Qian]

Thanks you very much, fixed the problem :)

On Mon, Jan 22, 2018 at 4:28 PM, Random832 <random832 at fastmail.com> wrote:

> On Mon, Jan 22, 2018, at 16:00, Jason Qian via Python-list wrote:
> > Hello!
> >
> >   I am using ctypes on Windows to interface with a dll  and it works fine
> > on Linux and windows 32-bit python.  But, when using 64-bit python, we
> got
> > error "exception: access violation writing 0xFFFFFFFF99222A60".
>
> You are treating the obj type (myPythonAPI *) as c_int, which is only 32
> bits. You should be using a pointer type instead (ideally you should be
> using void * and c_void_p, so Python doesn't need the class definition.)
> Don't forget to set lib.loadInstance.restype as well.
>
> > __declspec(dllexport) myPythonAPI* loadInstance(){ return new
> > myPythonAPI(); }
> > __declspec(dllexport) int createService(myPythonAPI* obj, const char*
> > serviceName) { eturn obj->createService(serviceName);
>
> > lib = cdll.LoadLibrary('xxxxxxx.dll')
> >
> > lib.createService.argtypes=[c_int,ctypes.c_char_p]
> > lib.createService.restype=ctypes.c_int
> >
> > class myDriver(object):
> > def init(self):
> > self.obj = lib.loadInstance()
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>