New submission from Florian Schulze <florian.schulze@gmx.net>: When I run the code below I consistently get a segfault a few seconds after touching the trackpad with several fingers. Even if I do nothing inside the callback except "return 0" I get the segfault. It seems like MTDeviceStart spawns a new thread in which the callback is called. It works fine with Python 2.7.5. import time import ctypes import threading CFArrayRef = ctypes.c_void_p CFMutableArrayRef = ctypes.c_void_p CFIndex = ctypes.c_long MultitouchSupport = ctypes.CDLL("/System/Library/PrivateFrameworks/MultitouchSupport.framework/MultitouchSupport") CFArrayGetCount = MultitouchSupport.CFArrayGetCount CFArrayGetCount.argtypes = [CFArrayRef] CFArrayGetCount.restype = CFIndex CFArrayGetValueAtIndex = MultitouchSupport.CFArrayGetValueAtIndex CFArrayGetValueAtIndex.argtypes = [CFArrayRef, CFIndex] CFArrayGetValueAtIndex.restype = ctypes.c_void_p MTDeviceCreateList = MultitouchSupport.MTDeviceCreateList MTDeviceCreateList.argtypes = [] MTDeviceCreateList.restype = CFMutableArrayRef class MTPoint(ctypes.Structure): _fields_ = [("x", ctypes.c_float), ("y", ctypes.c_float)] class MTVector(ctypes.Structure): _fields_ = [("position", MTPoint), ("velocity", MTPoint)] class MTData(ctypes.Structure): _fields_ = [ ("frame", ctypes.c_int), ("timestamp", ctypes.c_double), ("identifier", ctypes.c_int), ("state", ctypes.c_int), # Current state (of unknown meaning). ("unknown1", ctypes.c_int), ("unknown2", ctypes.c_int), ("normalized", MTVector), # Normalized position and vector of # the touch (0 to 1). ("size", ctypes.c_float), # The area of the touch. ("unknown3", ctypes.c_int), # The following three define the ellipsoid of a finger. ("angle", ctypes.c_float), ("major_axis", ctypes.c_float), ("minor_axis", ctypes.c_float), ("unknown4", MTVector), ("unknown5_1", ctypes.c_int), ("unknown5_2", ctypes.c_int), ("unknown6", ctypes.c_float), ] MTDataRef = ctypes.POINTER(MTData) MTContactCallbackFunction = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int, MTDataRef, ctypes.c_int, ctypes.c_double, ctypes.c_int) MTDeviceRef = ctypes.c_void_p MTRegisterContactFrameCallback = MultitouchSupport.MTRegisterContactFrameCallback MTRegisterContactFrameCallback.argtypes = [MTDeviceRef, MTContactCallbackFunction] MTRegisterContactFrameCallback.restype = None MTDeviceStart = MultitouchSupport.MTDeviceStart MTDeviceStart.argtypes = [MTDeviceRef, ctypes.c_int] MTDeviceStart.restype = None ### @MTContactCallbackFunction def my_callback(device, data_ptr, n_fingers, timestamp, frame): print threading.current_thread(), device, data_ptr, n_fingers, timestamp, frame for i in xrange(n_fingers): data = data_ptr[i] d = "x=%.2f, y=%.2f" % (data.normalized.position.x * 100, data.normalized.position.y * 100) print "%d: %s" % (i, d) return 0 devices = MultitouchSupport.MTDeviceCreateList() num_devices = CFArrayGetCount(devices) print "num_devices =", num_devices for i in xrange(num_devices): device = CFArrayGetValueAtIndex(devices, i) print "device #%d: %016x" % (i, device) MTRegisterContactFrameCallback(device, my_callback) MTDeviceStart(device, 0) print threading.current_thread() while threading.active_count(): # Why sleep instead of join? Ask David Beazley. time.sleep(0.125) ---------- messages: 6107 nosy: fschulze, pypy-issue priority: bug status: unread title: segfault with ctypes callback on OS X ________________________________________ PyPy bug tracker <tracker@bugs.pypy.org> <https://bugs.pypy.org/issue1593> ________________________________________