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diff --git a/Lib/ctypes/test/test_parameters.py b/Lib/ctypes/test/test_parameters.py
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index 82704d5..5894d88 100644
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--- a/Lib/ctypes/test/test_parameters.py
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+++ b/Lib/ctypes/test/test_parameters.py
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@@ -181,6 +181,49 @@ class SimpleTypesTestCase(unittest.TestCase):
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         # ArgumentError: argument 1: ValueError: 99
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         self.assertRaises(ArgumentError, func, 99)
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+    def test_parameter_repr(self):
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+        from ctypes import (
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+            c_bool,
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+            c_char,
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+            c_wchar,
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+            c_byte,
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+            c_ubyte,
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+            c_short,
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+            c_ushort,
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+            c_int,
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+            c_uint,
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+            c_long,
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+            c_ulong,
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+            c_longlong,
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+            c_ulonglong,
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+            c_float,
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+            c_double,
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+            c_longdouble,
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+            c_char_p,
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+            c_wchar_p,
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+            c_void_p,
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+        )
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+        self.assertRegexpMatches(repr(c_bool.from_param(True)), r"^<cparam '\?' at 0x[A-Fa-f0-9]+>$")
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+        self.assertEqual(repr(c_char.from_param('a')), "<cparam 'c' ('a')>")
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+        self.assertRegexpMatches(repr(c_wchar.from_param('a')), r"^<cparam 'u' at 0x[A-Fa-f0-9]+>$")
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+        self.assertEqual(repr(c_byte.from_param(98)), "<cparam 'b' (98)>")
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+        self.assertEqual(repr(c_ubyte.from_param(98)), "<cparam 'B' (98)>")
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+        self.assertEqual(repr(c_short.from_param(511)), "<cparam 'h' (511)>")
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+        self.assertEqual(repr(c_ushort.from_param(511)), "<cparam 'H' (511)>")
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+        self.assertRegexpMatches(repr(c_int.from_param(20000)), r"^<cparam '[li]' \(20000\)>$")
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+        self.assertRegexpMatches(repr(c_uint.from_param(20000)), r"^<cparam '[LI]' \(20000\)>$")
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+        self.assertRegexpMatches(repr(c_long.from_param(20000)), r"^<cparam '[li]' \(20000\)>$")
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+        self.assertRegexpMatches(repr(c_ulong.from_param(20000)), r"^<cparam '[LI]' \(20000\)>$")
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+        self.assertRegexpMatches(repr(c_longlong.from_param(20000)), r"^<cparam '[liq]' \(20000\)>$")
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+        self.assertRegexpMatches(repr(c_ulonglong.from_param(20000)), r"^<cparam '[LIQ]' \(20000\)>$")
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+        self.assertEqual(repr(c_float.from_param(1.5)), "<cparam 'f' (1.5)>")
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+        self.assertEqual(repr(c_double.from_param(1.5)), "<cparam 'd' (1.5)>")
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+        self.assertEqual(repr(c_double.from_param(1e300)), "<cparam 'd' (1e+300)>")
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+        self.assertRegexpMatches(repr(c_longdouble.from_param(1.5)), r"^<cparam ('d' \(1.5\)|'g' at 0x[A-Fa-f0-9]+)>$")
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+        self.assertRegexpMatches(repr(c_char_p.from_param(b'hihi')), "^<cparam 'z' \(0x[A-Fa-f0-9]+\)>$")
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+        self.assertRegexpMatches(repr(c_wchar_p.from_param('hihi')), "^<cparam 'Z' \(0x[A-Fa-f0-9]+\)>$")
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+        self.assertRegexpMatches(repr(c_void_p.from_param(0x12)), r"^<cparam 'P' \(0x0*12\)>$")
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+
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 ################################################################
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diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
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index 6daf455..dac24b4 100644
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--- a/Modules/_ctypes/callproc.c
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+++ b/Modules/_ctypes/callproc.c
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@@ -449,54 +449,62 @@ PyCArg_dealloc(PyCArgObject *self)
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 static PyObject *
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 PyCArg_repr(PyCArgObject *self)
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 {
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-    char buffer[256];
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     switch(self->tag) {
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     case 'b':
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     case 'B':
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-        sprintf(buffer, "<cparam '%c' (%d)>",
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+        return PyString_FromFormat("<cparam '%c' (%d)>",
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             self->tag, self->value.b);
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-        break;
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     case 'h':
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     case 'H':
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-        sprintf(buffer, "<cparam '%c' (%d)>",
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+        return PyString_FromFormat("<cparam '%c' (%d)>",
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             self->tag, self->value.h);
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-        break;
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     case 'i':
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     case 'I':
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-        sprintf(buffer, "<cparam '%c' (%d)>",
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+        return PyString_FromFormat("<cparam '%c' (%d)>",
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             self->tag, self->value.i);
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-        break;
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     case 'l':
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     case 'L':
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-        sprintf(buffer, "<cparam '%c' (%ld)>",
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+        return PyString_FromFormat("<cparam '%c' (%ld)>",
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             self->tag, self->value.l);
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-        break;
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 #ifdef HAVE_LONG_LONG
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     case 'q':
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     case 'Q':
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-        sprintf(buffer,
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-#ifdef MS_WIN32
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-            "<cparam '%c' (%I64d)>",
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-#else
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-            "<cparam '%c' (%qd)>",
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-#endif
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+        return PyString_FromFormat("<cparam '%c' (%lld)>",
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             self->tag, self->value.q);
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-        break;
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 #endif
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     case 'd':
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-        sprintf(buffer, "<cparam '%c' (%f)>",
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-            self->tag, self->value.d);
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-        break;
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-    case 'f':
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-        sprintf(buffer, "<cparam '%c' (%f)>",
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-            self->tag, self->value.f);
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-        break;
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-
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+    case 'f': {
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+        PyObject *s = PyString_FromFormat("<cparam '%c' (", self->tag);
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+        if (s == NULL) {
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+            return NULL;
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+        }
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+        PyObject *f = PyFloat_FromDouble((self->tag == 'f') ? self->value.f : self->value.d);
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+        if (f == NULL) {
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+            Py_DECREF(s);
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+            return NULL;
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+        }
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+        PyObject *r = PyObject_Repr(f);
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+        Py_DECREF(f);
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+        if (r == NULL) {
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+            Py_DECREF(s);
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+            return NULL;
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+        }
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+        PyString_ConcatAndDel(&s, r);
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+        if (s == NULL) {
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+            return NULL;
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+        }
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+        r = PyString_FromString(")>");
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+        if (r == NULL) {
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+            Py_DECREF(s);
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+            return NULL;
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+        }
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+        PyString_ConcatAndDel(&s, r);
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+        return s;
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+    }
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     case 'c':
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-        sprintf(buffer, "<cparam '%c' (%c)>",
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+        return PyString_FromFormat("<cparam '%c' ('%c')>",
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             self->tag, self->value.c);
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-        break;
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 /* Hm, are these 'z' and 'Z' codes useful at all?
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    Shouldn't they be replaced by the functionality of c_string
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@@ -505,16 +513,13 @@ PyCArg_repr(PyCArgObject *self)
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     case 'z':
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     case 'Z':
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     case 'P':
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-        sprintf(buffer, "<cparam '%c' (%p)>",
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+        return PyUnicode_FromFormat("<cparam '%c' (%p)>",
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             self->tag, self->value.p);
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-        break;
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     default:
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-        sprintf(buffer, "<cparam '%c' at %p>",
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-            self->tag, self);
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-        break;
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+        return PyString_FromFormat("<cparam '%c' at %p>",
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+            (unsigned char)self->tag, (void *)self);
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     }
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-    return PyString_FromString(buffer);
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 }
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 static PyMemberDef PyCArgType_members[] = {