gh-143304: Fix ctypes.CDLL to honor handle parameter on POSIX systems

Lib/ctypes/__init__.py

@@ -440,6 +440,9 @@ def _load_library(self, name, mode, handle, winmode):
 
     else:
         def _load_library(self, name, mode, handle, winmode):
+            if handle is not None:
+                self._name = name
+                return handle
             # If the filename that has been provided is an iOS/tvOS/watchOS
             # .fwork file, dereference the location to the true origin of the
             # binary.

Lib/test/test_ctypes/test_loading.py

@@ -106,6 +106,14 @@ def test_load_without_name_and_with_handle(self):
         lib = ctypes.WinDLL(name=None, handle=handle)
         self.assertIs(handle, lib._handle)
 
+    @unittest.skipIf(os.name == "nt", 'POSIX-specific test')
+    @unittest.skipIf(libc_name is None, 'could not find libc')
+    def test_load_without_name_and_with_handle_posix(self):
+        lib1 = CDLL(libc_name)
+        handle = lib1._handle
+        lib2 = CDLL(name=None, handle=handle)
+        self.assertIs(handle, lib2._handle)
+
     @unittest.skipUnless(os.name == "nt", 'Windows-specific test')
     def test_1703286_A(self):
         # On winXP 64-bit, advapi32 loads at an address that does

Misc/NEWS.d/next/Library/2026-01-01-05-26-00.gh-issue-143304.Kv7x9Q.rst

@@ -0,0 +1 @@
+Fix :class:`ctypes.CDLL` to honor the ``handle`` parameter on POSIX systems.