Wander, Earlier, I mentioned that the openusb backend did not work for me on MacOS, but I'm pretty sure I found the problem. There seems to be a typo in backend/openusb.py on line #155, where it configures the return type for the function "openusb_init" - this line refers to the function as "openusb" rather then "openusb_init":
$ diff -u openusb.py.orig openusb.py --- openusb.py.orig 2010-07-12 08:51:37.000000000 -0400 +++ openusb.py 2010-07-12 08:51:49.000000000 -0400 @@ -152,7 +152,7 @@ def _setup_prototypes(lib): # int32_t openusb_init(uint32_t flags , openusb_handle_t *handle); lib.openusb_init.argtypes = [c_uint32, POINTER(_openusb_handle)] - lib.openusb.restype = c_int32 + lib.openusb_init.restype = c_int32 # void openusb_fini(openusb_handle_t handle ); lib.openusb_fini.argtypes = [_openusb_handle] After making this fix, my test code was able to successfully use the openusb backend to iterate over all my USB devices. The download code archive this occurs in is named, "pyusb-1.0.0-a0.zip". Thanks, Chris Wolf Error before patch: >>> import ctypes.util >>> import usb.backend.openusb >>> libname = ctypes.util.find_library('openusb') >>> lib = ctypes.util.CDLL(libname) >>> usbbe = usb.backend.openusb.get_backend() 2010-07-11 14:58:19,869 ERROR:usb.backend.openusb:Error loading OpenUSB backend Traceback (most recent call last): File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/usb/backend/openusb.py", line 589, in get_backend _setup_prototypes(_lib) File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/usb/backend/openusb.py", line 155, in _setup_prototypes lib.openusb.restype = c_int32 File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/ctypes/__init__.py", line 353, in __getattr__ func = self.__getitem__(name) File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/ctypes/__init__.py", line 358, in __getitem__ func = self._FuncPtr((name_or_ordinal, self)) AttributeError: dlsym(0x722c10, openusb): symbol not found ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ pyusb-users mailing list pyusb-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pyusb-users