import unittest

from ctypes import *



import _ctypes_test



class ReturnFuncPtrTestCase(unittest.TestCase):



    def test_with_prototype(self):

        # The _ctypes_test shared lib/dll exports quite some functions for testing.

        # The get_strchr function returns a *pointer* to the C strchr function.

        dll = CDLL(_ctypes_test.__file__)

        get_strchr = dll.get_strchr

        get_strchr.restype = CFUNCTYPE(c_char_p, c_char_p, c_char)

        strchr = get_strchr()

        self.failUnlessEqual(strchr("abcdef", "b"), "bcdef")

        self.failUnlessEqual(strchr("abcdef", "x"), None)

        self.assertRaises(ArgumentError, strchr, "abcdef", 3)

        self.assertRaises(TypeError, strchr, "abcdef")



    def test_without_prototype(self):

        dll = CDLL(_ctypes_test.__file__)

        get_strchr = dll.get_strchr

        # the default 'c_int' would not work on systems where sizeof(int) != sizeof(void *)

        get_strchr.restype = c_void_p

        addr = get_strchr()

        # _CFuncPtr instances are now callable with an integer argument

        # which denotes a function address:

        strchr = CFUNCTYPE(c_char_p, c_char_p, c_char)(addr)

        self.failUnless(strchr("abcdef", "b"), "bcdef")

        self.failUnlessEqual(strchr("abcdef", "x"), None)

        self.assertRaises(ArgumentError, strchr, "abcdef", 3)

        self.assertRaises(TypeError, strchr, "abcdef")



if __name__ == "__main__":

    unittest.main()

