Issue #22980: Under Linux, C extensions now include bitness in the file name,

to make it easy to test 32-bit and 64-bit builds in the same working tree.

Lib/test/test_sysconfig.py

@@ -389,6 +389,12 @@ class TestSysConfig(unittest.TestCase):
         self.assertIsNotNone(vars['SO'])
         self.assertEqual(vars['SO'], vars['EXT_SUFFIX'])
 
+    @unittest.skipUnless(sys.platform == 'linux', 'Linux-specific test')
+    def test_bitness_in_ext_suffix(self):
+        suffix = sysconfig.get_config_var('EXT_SUFFIX')
+        bitness = '-32b' if sys.maxsize < 2**32 else '-64b'
+        self.assertTrue(suffix.endswith(bitness + '.so'), suffix)
+
 
 class MakefileTests(unittest.TestCase):
 

Misc/NEWS

@@ -10,6 +10,10 @@ Release date: 2015-03-08
 Core and Builtins
 -----------------
 
+- Issue #22980: Under Linux, C extensions now include bitness in the file
+  name, to make it easy to test 32-bit and 64-bit builds in the same
+  working tree.
+
 - Issue #23571: PyObject_Call() and PyCFunction_Call() now raise a SystemError
   if a function returns a result and raises an exception. The SystemError is
   chained to the previous exception.

configure

@@ -14200,7 +14200,15 @@ $as_echo_n "checking ABIFLAGS... " >&6; }
 $as_echo "$ABIFLAGS" >&6; }
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking SOABI" >&5
 $as_echo_n "checking SOABI... " >&6; }
-SOABI='cpython-'`echo $VERSION | tr -d .`${ABIFLAGS}
+
+case $ac_sys_system in
+    Linux*|GNU*)
+        BITNESS_SUFFIX=-$(($ac_cv_sizeof_void_p * 8))b;;
+    *)
+        BITNESS_SUFFIX=;;
+esac
+SOABI='cpython-'`echo $VERSION | tr -d .`${ABIFLAGS}${BITNESS_SUFFIX}
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $SOABI" >&5
 $as_echo "$SOABI" >&6; }
 

configure.ac

@@ -4175,7 +4175,15 @@ AC_SUBST(SOABI)
 AC_MSG_CHECKING(ABIFLAGS)
 AC_MSG_RESULT($ABIFLAGS)
 AC_MSG_CHECKING(SOABI)
-SOABI='cpython-'`echo $VERSION | tr -d .`${ABIFLAGS}
+
+case $ac_sys_system in
+    Linux*|GNU*)
+        BITNESS_SUFFIX=-$(($ac_cv_sizeof_void_p * 8))b;;
+    *)
+        BITNESS_SUFFIX=;;
+esac
+SOABI='cpython-'`echo $VERSION | tr -d .`${ABIFLAGS}${BITNESS_SUFFIX}
+
 AC_MSG_RESULT($SOABI)
 
 AC_SUBST(EXT_SUFFIX)