Minimal example: >>> import ctypes >>> x = ctypes.c_double.from_param(1e300) >>> repr(x) Segmentation fault This happens when getting the string repre

Minimal example: >>> import ctypes >>> x = ctypes.c_double.from_param(1e300) >>> repr(x) Segmentation fault This happens when getting the string representation of a foreign function float. It doesn't affect the standard builtin float type. So it's not extremely common. But I can imagine this cropping up if you e.g. find a way to cause an exception that formats a value. Or if there's aggressive logging.