import ctypes

class Error(ctypes.Structure):

_fields_ = [('err', ctypes.c_char_p)]

def __del__(self):

# We can call del_error with a None err, but this way we can avoid

# the call overhead when it's not necessary.

if self.err is not None:

del_error(self)

def raise_if_err(self):

if self.err is not None:

raise IOError(self.err.decode())

class EvenResult(ctypes.Structure):

# Multiple return values can be grabbed in a struct.

_fields_ = [

('result', ctypes.c_bool),

('err', Error),

]

lib = ctypes.CDLL('./error.so')

del_error = lib.delError

del_error.argtypes = [Error]

even = lib.even

even.argtypes = [ctypes.c_int64]

even.restype = EvenResult

for i in (0, 1, 2, 3, -5):

e = even(i)

try:

e.err.raise_if_err()

except IOError as err:

print('Error:', err)

continue

print(i, 'even:', e.result)