gh-148675: Add Zd/Zf formats to array, ctypes, memoryview, struct

Doc/library/array.rst

@@ -52,6 +52,10 @@ defined:
 +-----------+--------------------+-------------------+-----------------------+-------+
 | ``'D'``   | double complex     | complex           | 16                    | \(4)  |
 +-----------+--------------------+-------------------+-----------------------+-------+
+| ``'Zf'``  | float complex      | complex           | 8                     | \(4)  |
++-----------+--------------------+-------------------+-----------------------+-------+
+| ``'Zd'``  | double complex     | complex           | 16                    | \(4)  |
++-----------+--------------------+-------------------+-----------------------+-------+
 
 
 Notes:
@@ -80,7 +84,7 @@ Notes:
    .. versionadded:: 3.15
 
 (4)
-   Complex types (``F`` and ``D``) are available unconditionally,
+   Complex types (``F``, ``D``, ``Zf`` and ``Zd``) are available unconditionally,
    regardless on support for complex types (the Annex G of the C11 standard)
    by the C compiler.
    As specified in the C11 standard, each complex type is represented by a

Doc/library/struct.rst

@@ -264,6 +264,10 @@ platform-dependent.
 +--------+--------------------------+--------------------+----------------+------------+
 | ``D``  | :c:expr:`double complex` | complex            | 16             | \(10)      |
 +--------+--------------------------+--------------------+----------------+------------+
+| ``Zf`` | :c:expr:`float complex`  | complex            | 8              | \(10)      |
++--------+--------------------------+--------------------+----------------+------------+
+| ``Zd`` | :c:expr:`double complex` | complex            | 16             | \(10)      |
++--------+--------------------------+--------------------+----------------+------------+
 | ``s``  | :c:expr:`char[]`         | bytes              |                | \(9)       |
 +--------+--------------------------+--------------------+----------------+------------+
 | ``p``  | :c:expr:`char[]`         | bytes              |                | \(8)       |
@@ -280,6 +284,9 @@ platform-dependent.
 .. versionchanged:: 3.14
    Added support for the ``'F'`` and ``'D'`` formats.
 
+.. versionchanged:: next
+   Added support for the ``'Zf'`` and ``'Zd'`` formats.
+
 .. seealso::
 
    The :mod:`array` and :ref:`ctypes <ctypes-fundamental-data-types>` modules,
@@ -368,7 +375,7 @@ Notes:
    For the ``'F'`` and ``'D'`` format characters, the packed representation uses
    the IEEE 754 binary32 and binary64 format for components of the complex
    number, regardless of the floating-point format used by the platform.
-   Note that complex types (``F`` and ``D``) are available unconditionally,
+   Note that complex types (``F``/``Zf`` and ``D``/``Zd``) are available unconditionally,
    despite complex types being an optional feature in C.
    As specified in the C11 standard, each complex type is represented by a
    two-element C array containing, respectively, the real and imaginary parts.

Doc/whatsnew/3.15.rst

@@ -679,7 +679,7 @@ array
 -----
 
 * Support the :c:expr:`float complex` and :c:expr:`double complex` C types:
-  formatting characters ``'F'`` and ``'D'`` respectively.
+  formatting characters ``'F'``/``'Zd'`` and ``'D'``/``'Zd'`` respectively.
   (Contributed by Sergey B Kirpichev in :gh:`146151`.)
 
 * Support half-floats (16-bit IEEE 754 binary interchange format): formatting

Lib/test/test_array.py

@@ -42,7 +42,7 @@ def test_array_is_sequence(self):
     def test_bad_constructor(self):
         self.assertRaises(TypeError, array.array)
         self.assertRaises(TypeError, array.array, spam=42)
-        self.assertRaises(TypeError, array.array, 'xx')
+        self.assertRaises(ValueError, array.array, 'xx')
         self.assertRaises(ValueError, array.array, 'x')
 
     @support.cpython_only

Lib/test/test_ctypes/test_c_simple_type_meta.py

@@ -221,6 +221,8 @@ class F(metaclass=PyCSimpleType):
         if not MS_WINDOWS:
             expected_type_chars.remove('X')
         self.assertIn("'" + ''.join(expected_type_chars) + "'", message)
+        if hasattr(ctypes, 'c_float_complex'):
+            self.assertIn("'Zf', 'Zd', 'Zg'", message)
 
     def test_creating_pointer_in_dunder_init_3(self):
         """Check if interfcase subclasses properly creates according internal

Lib/test/test_ctypes/test_numbers.py

@@ -119,8 +119,20 @@ def test_floats(self):
     @unittest.skipUnless(hasattr(ctypes, "c_double_complex"),
                          "requires C11 complex type")
     def test_complex(self):
+        class c_double_complex2(ctypes._SimpleCData):
+            _type_ = "Zd"
+        ctypes._check_size(c_double_complex2)
+
+        class c_float_complex2(ctypes._SimpleCData):
+            _type_ = "Zf"
+        ctypes._check_size(c_float_complex2)
+
+        class c_longdouble_complex2(ctypes._SimpleCData):
+            _type_ = "Zg"
+
         for t in [ctypes.c_double_complex, ctypes.c_float_complex,
-                  ctypes.c_longdouble_complex]:
+                  ctypes.c_longdouble_complex,
+                  c_double_complex2, c_float_complex2, c_longdouble_complex2]:
             self.assertEqual(t(1).value, 1+0j)
             self.assertEqual(t(1.0).value, 1+0j)
             self.assertEqual(t(1+0.125j).value, 1+0.125j)

Lib/test/test_memoryview.py

@@ -637,7 +637,7 @@ def check_equal(view, is_equal):
                 check_equal(m, True)
 
         # Test complex formats
-        for complex_format in 'FD':
+        for complex_format in ('F', 'D', 'Zf', 'Zd'):
             with self.subTest(format=complex_format):
                 data = struct.pack(complex_format * 3, 1.0, 2.0, float('nan'))
                 m = memoryview(data).cast(complex_format)
@@ -723,6 +723,10 @@ def test_complex_types(self):
         double_complex_view = memoryview(double_complex_data).cast('D')
         self.assertEqual(float_complex_view.nbytes * 2, double_complex_view.nbytes)
         self.assertListEqual(float_complex_view.tolist(), double_complex_view.tolist())
+        float_complex_view = memoryview(float_complex_data).cast('Zf')
+        double_complex_view = memoryview(double_complex_data).cast('Zd')
+        self.assertEqual(float_complex_view.nbytes * 2, double_complex_view.nbytes)
+        self.assertListEqual(float_complex_view.tolist(), double_complex_view.tolist())
 
     def test_memoryview_hex(self):
         # Issue #9951: memoryview.hex() segfaults with non-contiguous buffers.

Lib/test/test_struct.py

@@ -995,7 +995,11 @@ def test_c_complex_round_trip(self):
         values = [complex(*_) for _ in combinations([1, -1, 0.0, -0.0, 2,
                                                      -3, INF, -INF, NAN], 2)]
         for z in values:
-            for f in ['F', 'D', '>F', '>D', '<F', '<D']:
+            for f in [
+                'F', 'D', 'Zf', 'Zd',
+                '>F', '>D', '>Zf', '>Zd',
+                '<F', '<D', '<Zf', '<Zd',
+            ]:
                 with self.subTest(z=z, format=f):
                     round_trip = struct.unpack(f, struct.pack(f, z))[0]
                     self.assertComplexesAreIdentical(z, round_trip)

Misc/NEWS.d/next/Library/2026-04-17-13-56-44.gh-issue-148675.f1kG70.rst

@@ -0,0 +1,3 @@
+:mod:`array`, :mod:`ctypes`, :mod:`struct`: Add support for ``Zd`` and ``Zf``
+format for double complex and float complex. Add also support for ``Zg``
+format for long double complex to :mod:`ctypes`. Patch by Victor Stinner.

Modules/_ctypes/_ctypes.c

@@ -2315,7 +2315,6 @@ PyCSimpleType_init(PyObject *self, PyObject *args, PyObject *kwds)
 {
     PyObject *proto;
     const char *proto_str;
-    Py_ssize_t proto_len;
     PyMethodDef *ml;
     struct fielddesc *fmt;
 
@@ -2333,27 +2332,33 @@ PyCSimpleType_init(PyObject *self, PyObject *args, PyObject *kwds)
         return -1;
     }
     if (PyUnicode_Check(proto)) {
-        proto_str = PyUnicode_AsUTF8AndSize(proto, &proto_len);
+        proto_str = PyUnicode_AsUTF8(proto);
         if (!proto_str)
             goto error;
     } else {
         PyErr_SetString(PyExc_TypeError,
             "class must define a '_type_' string attribute");
         goto error;
     }
-    if (proto_len != 1) {
-        PyErr_SetString(PyExc_ValueError,
-                        "class must define a '_type_' attribute "
-                        "which must be a string of length 1");
-        goto error;
-    }
     fmt = _ctypes_get_fielddesc(proto_str);
     if (!fmt) {
-        PyErr_Format(PyExc_AttributeError,
-                     "class must define a '_type_' attribute which must be\n"
-                     "a single character string containing one of the\n"
-                     "supported types: '%s'.",
-                     _ctypes_get_simple_type_chars());
+        const char *complex_formats = _ctypes_get_complex_type_formats();
+        if (complex_formats) {
+            PyErr_Format(PyExc_AttributeError,
+                         "class must define a '_type_' attribute which must be\n"
+                         "a single character string containing one of the\n"
+                         "supported types: '%s', or one of these strings:\n"
+                         "%s.",
+                         _ctypes_get_simple_type_chars(),
+                         complex_formats);
+        }
+        else {
+            PyErr_Format(PyExc_AttributeError,
+                         "class must define a '_type_' attribute which must be\n"
+                         "a single character string containing one of the\n"
+                         "supported types: '%s'.\n",
+                         _ctypes_get_simple_type_chars());
+        }
         goto error;
     }
 

Modules/_ctypes/callproc.c

@@ -641,9 +641,9 @@ union result {
     double d;
     float f;
     void *p;
-    double D[2];
-    float F[2];
-    long double G[2];
+    double Zd[2];
+    float Zf[2];
+    long double Zg[2];
 };
 
 struct argument {