numpy
diff --git a/‎numpy/core/_dtype_ctypes.py
Lines changed: 27 additions & 6 deletions b/‎numpy/core/_dtype_ctypes.py
Lines changed: 27 additions & 6 deletions
diff --git a/‎numpy/core/tests/test_dtype.py
Lines changed: 19 additions & 1 deletion b/‎numpy/core/tests/test_dtype.py
Lines changed: 19 additions & 1 deletion
@@ -33,17 +33,38 @@ def _from_ctypes_array(t):
 
 
 def _from_ctypes_structure(t):
-    # TODO: gh-10533, gh-10532
-    fields = []
+    # TODO: gh-10533
     for item in t._fields_:
         if len(item) > 2:
             raise TypeError(
                 "ctypes bitfields have no dtype equivalent")
-        fname, ftyp = item
-        fields.append((fname, dtype_from_ctypes_type(ftyp)))
 
-    # by default, ctypes structs are aligned
-    return np.dtype(fields, align=True)
+    if hasattr(t, "_pack_"):
+        formats = []
+        offsets = []
+        names = []
+        current_offset = 0
+        for fname, ftyp in t._fields_:
+            names.append(fname)
+            formats.append(dtype_from_ctypes_type(ftyp))
+            # Each type has a default offset, this is platform dependent for some types.
+            effective_pack = min(t._pack_, ctypes.alignment(ftyp))
+            current_offset = ((current_offset + effective_pack - 1) // effective_pack) * effective_pack
+            offsets.append(current_offset)
+            current_offset += ctypes.sizeof(ftyp)
+
+        return np.dtype(dict(
+            formats=formats,
+            offsets=offsets,
+            names=names,
+            itemsize=ctypes.sizeof(t)))
+    else:
+        fields = []
+        for fname, ftyp in t._fields_:
+            fields.append((fname, dtype_from_ctypes_type(ftyp)))
+
+        # by default, ctypes structs are aligned
+        return np.dtype(fields, align=True)
 
 
 def dtype_from_ctypes_type(t):
 
@@ -824,7 +824,6 @@ class Union(ctypes.Union):
         ))
         self.check(Union, expected)
 
-    @pytest.mark.xfail(reason="_pack_ is ignored - see gh-11651")
     def test_packed_structure(self):
         class PackedStructure(ctypes.Structure):
             _pack_ = 1
@@ -838,6 +837,25 @@ class PackedStructure(ctypes.Structure):
         ])
         self.check(PackedStructure, expected)
 
+    def test_large_packed_structure(self):
+        class PackedStructure(ctypes.Structure):
+            _pack_ = 2
+            _fields_ = [
+                ('a', ctypes.c_uint8),
+                ('b', ctypes.c_uint16),
+                ('c', ctypes.c_uint8),
+                ('d', ctypes.c_uint16),
+                ('e', ctypes.c_uint32),
+                ('f', ctypes.c_uint32),
+                ('g', ctypes.c_uint8)
+                ]
+        expected = np.dtype(dict(
+            formats=[np.uint8, np.uint16, np.uint8, np.uint16, np.uint32, np.uint32, np.uint8 ],
+            offsets=[0, 2, 4, 6, 8, 12, 16],
+            names=['a', 'b', 'c', 'd', 'e', 'f', 'g'],
+            itemsize=18))
+        self.check(PackedStructure, expected)
+
     @pytest.mark.xfail(sys.byteorder != 'little',
         reason="non-native endianness does not work - see gh-10533")
     def test_little_endian_structure(self):