Issue 1872: Changed the struct module typecode from 't' to '?', for

compatibility with PEP3118.

Doc/library/struct.rst

@@ -77,7 +77,7 @@ Python values should be obvious given their types:
 +--------+-------------------------+--------------------+-------+
 | ``B``  | :ctype:`unsigned char`  | integer            |       |
 +--------+-------------------------+--------------------+-------+
-| ``t``  | :ctype:`_Bool`          | bool               | \(1)  |
+| ``?``  | :ctype:`_Bool`          | bool               | \(1)  |
 +--------+-------------------------+--------------------+-------+
 | ``h``  | :ctype:`short`          | integer            |       |
 +--------+-------------------------+--------------------+-------+
@@ -110,7 +110,7 @@ Python values should be obvious given their types:
 Notes:
 
 (1)
-   The ``'t'`` conversion code corresponds to the :ctype:`_Bool` type defined by
+   The ``'?'`` conversion code corresponds to the :ctype:`_Bool` type defined by
    C99. If this type is not available, it is simulated using a :ctype:`char`. In
    standard mode, it is always represented by one byte.
 
@@ -158,7 +158,7 @@ may be used.  For example, the Alpha and Merced processors use 64-bit pointer
 values, meaning a Python long integer will be used to hold the pointer; other
 platforms use 32-bit pointers and will use a Python integer.
 
-For the ``'t'`` format character, the return value is either :const:`True` or
+For the ``'?'`` format character, the return value is either :const:`True` or
 :const:`False`. When packing, the truth value of the argument object is used.
 Either 0 or 1 in the native or standard bool representation will be packed, and
 any non-zero value will be True when unpacking.

Lib/ctypes/__init__.py

@@ -240,7 +240,7 @@ c_voidp = c_void_p # backwards compatibility (to a bug)
 _check_size(c_void_p)
 
 class c_bool(_SimpleCData):
-    _type_ = "t"
+    _type_ = "?"
 
 # This cache maps types to pointers to them.
 _pointer_type_cache = {}

Lib/test/test_struct.py

@@ -84,8 +84,8 @@ sz = struct.calcsize('i')
 if sz * 3 != struct.calcsize('iii'):
     raise TestFailed, 'inconsistent sizes'
 
-fmt = 'cbxxxxxxhhhhiillffdt'
-fmt3 = '3c3b18x12h6i6l6f3d3t'
+fmt = 'cbxxxxxxhhhhiillffd?'
+fmt3 = '3c3b18x12h6i6l6f3d3?'
 sz = struct.calcsize(fmt)
 sz3 = struct.calcsize(fmt3)
 if sz * 3 != sz3:
@@ -111,7 +111,7 @@ d = 3.1415
 t = True
 
 for prefix in ('', '@', '<', '>', '=', '!'):
-    for format in ('xcbhilfdt', 'xcBHILfdt'):
+    for format in ('xcbhilfd?', 'xcBHILfd?'):
         format = prefix + format
         if verbose:
             print "trying:", format
@@ -160,11 +160,11 @@ tests = [
     ('f', -2.0, '\300\000\000\000', '\000\000\000\300', 0),
     ('d', -2.0, '\300\000\000\000\000\000\000\000',
                '\000\000\000\000\000\000\000\300', 0),
-        ('t', 0, '\0', '\0', 0),
-        ('t', 3, '\1', '\1', 1),
-        ('t', True, '\1', '\1', 0),
-        ('t', [], '\0', '\0', 1),
-        ('t', (1,), '\1', '\1', 1),
+        ('?', 0, '\0', '\0', 0),
+        ('?', 3, '\1', '\1', 1),
+        ('?', True, '\1', '\1', 0),
+        ('?', [], '\0', '\0', 1),
+        ('?', (1,), '\1', '\1', 1),
 ]
 
 for fmt, arg, big, lil, asy in tests:
@@ -633,13 +633,13 @@ def test_bool():
         false = (), [], [], '', 0
         true = [1], 'test', 5, -1, 0xffffffffL+1, 0xffffffff/2
 
-        falseFormat = prefix + 't' * len(false)
+        falseFormat = prefix + '?' * len(false)
         if verbose:
             print 'trying bool pack/unpack on', false, 'using format', falseFormat
         packedFalse = struct.pack(falseFormat, *false)
         unpackedFalse = struct.unpack(falseFormat, packedFalse)
 
-        trueFormat = prefix + 't' * len(true)
+        trueFormat = prefix + '?' * len(true)
         if verbose:
             print 'trying bool pack/unpack on', true, 'using format', trueFormat
         packedTrue = struct.pack(trueFormat, *true)
@@ -658,10 +658,10 @@ def test_bool():
                 raise TestFailed('%r did not unpack as false' % t)
 
         if prefix and verbose:
-            print 'trying size of bool with format %r' % (prefix+'t')
-        packed = struct.pack(prefix+'t', 1)
+            print 'trying size of bool with format %r' % (prefix+'?')
+        packed = struct.pack(prefix+'?', 1)
 
-        if len(packed) != struct.calcsize(prefix+'t'):
+        if len(packed) != struct.calcsize(prefix+'?'):
             raise TestFailed('packed length is not equal to calculated size')
 
         if len(packed) != 1 and prefix:
@@ -670,7 +670,7 @@ def test_bool():
             print 'size of bool in native format is %i' % (len(packed))
 
         for c in '\x01\x7f\xff\x0f\xf0':
-            if struct.unpack('>t', c)[0] is not True:
+            if struct.unpack('>?', c)[0] is not True:
                 raise TestFailed('%c did not unpack as True' % c)
 
 test_bool()

Misc/NEWS

@@ -18,6 +18,9 @@ Core and builtins
 Library
 -------
 
+- Issue #1872: The struct module typecode for _Bool has been changed
+  from 't' to '?'.
+
 - The bundled libffi copy is now in sync with the recently released
   libffi3.0.4 version, apart from some small changes to
   Modules/_ctypes/libffi/configure.ac.

Modules/_ctypes/_ctypes.c

@@ -1242,7 +1242,7 @@ _type_ attribute.
 
 */
 
-static char *SIMPLE_TYPE_CHARS = "cbBhHiIlLdfuzZqQPXOvtg";
+static char *SIMPLE_TYPE_CHARS = "cbBhHiIlLdfuzZqQPXOv?g";
 
 static PyObject *
 c_wchar_p_from_param(PyObject *type, PyObject *value)

Modules/_ctypes/_ctypes_test.c

@@ -25,6 +25,15 @@
 
 /* some functions handy for testing */
 
+EXPORT(void)testfunc_array(int values[4])
+{
+	printf("testfunc_array %d %d %d %d\n",
+	       values[0],
+	       values[1],
+	       values[2],
+	       values[3]);
+}
+
 EXPORT(long double)testfunc_Ddd(double a, double b)
 {
 	long double result = (long double)(a * b);

Modules/_ctypes/cfield.c

@@ -726,7 +726,7 @@ vBOOL_get(void *ptr, Py_ssize_t size)
 #endif
 
 static PyObject *
-t_set(void *ptr, PyObject *value, Py_ssize_t size)
+bool_set(void *ptr, PyObject *value, Py_ssize_t size)
 {
 	switch (PyObject_IsTrue(value)) {
 	case -1:
@@ -741,7 +741,7 @@ t_set(void *ptr, PyObject *value, Py_ssize_t size)
 }
 
 static PyObject *
-t_get(void *ptr, Py_ssize_t size)
+bool_get(void *ptr, Py_ssize_t size)
 {
 	return PyBool_FromLong((long)*(BOOL_TYPE *)ptr);
 }
@@ -1645,15 +1645,15 @@ static struct fielddesc formattable[] = {
 	{ 'v', vBOOL_set, vBOOL_get, &ffi_type_sshort},
 #endif
 #if SIZEOF__BOOL == 1
-	{ 't', t_set, t_get, &ffi_type_uchar}, /* Also fallback for no native _Bool support */
+	{ '?', bool_set, bool_get, &ffi_type_uchar}, /* Also fallback for no native _Bool support */
 #elif SIZEOF__BOOL == SIZEOF_SHORT
-	{ 't', t_set, t_get, &ffi_type_ushort},
+	{ '?', bool_set, bool_get, &ffi_type_ushort},
 #elif SIZEOF__BOOL == SIZEOF_INT
-	{ 't', t_set, t_get, &ffi_type_uint, I_set_sw, I_get_sw},
+	{ '?', bool_set, bool_get, &ffi_type_uint, I_set_sw, I_get_sw},
 #elif SIZEOF__BOOL == SIZEOF_LONG
-	{ 't', t_set, t_get, &ffi_type_ulong, L_set_sw, L_get_sw},
+	{ '?', bool_set, bool_get, &ffi_type_ulong, L_set_sw, L_get_sw},
 #elif SIZEOF__BOOL == SIZEOF_LONG_LONG
-	{ 't', t_set, t_get, &ffi_type_ulong, Q_set_sw, Q_get_sw},
+	{ '?', bool_set, bool_get, &ffi_type_ulong, Q_set_sw, Q_get_sw},
 #endif /* SIZEOF__BOOL */
 	{ 'O', O_set, O_get, &ffi_type_pointer},
 	{ 0, NULL, NULL, NULL},

Modules/_struct.c

@@ -799,7 +799,7 @@ static formatdef native_table[] = {
 	{'q',	sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_longlong, np_longlong},
 	{'Q',	sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_ulonglong,np_ulonglong},
 #endif
-	{'t',	sizeof(BOOL_TYPE),	BOOL_ALIGN,	nu_bool,	np_bool},
+	{'?',	sizeof(BOOL_TYPE),	BOOL_ALIGN,	nu_bool,	np_bool},
 	{'f',	sizeof(float),	FLOAT_ALIGN,	nu_float,	np_float},
 	{'d',	sizeof(double),	DOUBLE_ALIGN,	nu_double,	np_double},
 	{'P',	sizeof(void *),	VOID_P_ALIGN,	nu_void_p,	np_void_p},
@@ -1036,7 +1036,7 @@ static formatdef bigendian_table[] = {
 	{'L',	4,		0,		bu_uint,	bp_uint},
 	{'q',	8,		0,		bu_longlong,	bp_longlong},
 	{'Q',	8,		0,		bu_ulonglong,	bp_ulonglong},
-	{'t',	1,		0,		bu_bool,	bp_bool},
+	{'?',	1,		0,		bu_bool,	bp_bool},
 	{'f',	4,		0,		bu_float,	bp_float},
 	{'d',	8,		0,		bu_double,	bp_double},
 	{0}
@@ -1255,7 +1255,7 @@ static formatdef lilendian_table[] = {
 	{'L',	4,		0,		lu_uint,	lp_uint},
 	{'q',	8,		0,		lu_longlong,	lp_longlong},
 	{'Q',	8,		0,		lu_ulonglong,	lp_ulonglong},
-	{'t',	1,		0,		bu_bool,	bp_bool}, /* Std rep not endian dep,
+	{'?',	1,		0,		bu_bool,	bp_bool}, /* Std rep not endian dep,
 		but potentially different from native rep -- reuse bx_bool funcs. */
 	{'f',	4,		0,		lu_float,	lp_float},
 	{'d',	8,		0,		lu_double,	lp_double},