gh-133143: Make information about the interpreter ABI more accessible

Doc/library/sys.rst

@@ -11,6 +11,51 @@ interpreter and to functions that interact strongly with the interpreter. It is
 always available. Unless explicitly noted otherwise, all variables are read-only.
 
 
+.. data:: abi_info
+
+ .. versionadded:: next
+
+ An object containing information about the ABI of the currently running
+ Python interpreter.
+ It should include information that affect the CPython ABI in ways that
+ require a specific build of the interpreter chosen from variants that can
+ co-exist on a single machine.
+ For example, it does not encode the base OS (Linux or Windows), but does
+ include pointer size since some systems support both 32- and 64-bit builds.
+ The available entries are the same on all platforms;
+ e.g. *pointer_size* is available even on 64-bit-only architectures.
+
+ The following attributes are available:
+
+ .. attribute:: abi_info.pointer_bits
+
+ The width of pointers in bits, as an integer,
+ equivalent to ``8 * sizeof(void *)``.
+ Usually, this is ``32`` or ``64``.
+
+ .. attribute:: abi_info.free_threaded
+
+ A Boolean indicating whether the interpreter was built with
+:term:`free threading` support.
+ This reflects either the presence of the :option:`--disable-gil`
+:file:`configure` option (on Unix)
+ or setting the ``DisableGil`` property (on Windows).
+
+ .. attribute:: abi_info.debug
+
+ A Boolean indicating whether the interpreter was built in
+:ref:`debug mode <debug-build>`.
+ This reflects either the presence of the :option:`--with-pydebug`
+:file:`configure` option (on Unix)
+ or the ``Debug`` configuration (on Windows).
+
+ .. attribute:: abi_info.byteorder
+
+ A string indicating the native byte order,
+ either ``'big'`` or ``'little'``.
+ This is the same as the :data:`byteorder` attribute.
+
+
 .. data:: abiflags
 
  On POSIX systems where Python was built with the standard ``configure``

Doc/whatsnew/3.15.rst

@@ -460,6 +460,13 @@ ssl
  (Contributed by Ron Frederick in :gh:`138252`.)
 
 
+sys
+---
+
+* Add :data:`sys.abi_info` namespace to improve access to ABI information.
+ (Contributed by Klaus Zimmermann in :gh:`137476`.)
+
+
 tarfile
 -------
 

Lib/test/test_sys.py

@@ -739,6 +739,20 @@ def test_thread_info(self):
 elifsys.platform=="wasi":
 self.assertEqual(info.name, "pthread-stubs")
 
+deftest_abi_info(self):
+info=sys.abi_info
+self.assertEqual(len(info.__dict__), 4)
+pointer_bits=64ifsys.maxsize>2**32else32
+self.assertEqual(info.pointer_bits, pointer_bits)
+self.assertEqual(info.byteorder, sys.byteorder)
+forattr, flagin [
+ ("free_threaded", "Py_GIL_DISABLED"),
+ ("debug", "Py_DEBUG"),
+ ]:
+self.assertEqual(getattr(info, attr, None),
+bool(sysconfig.get_config_var(flag)),
+f"for {attr}")
+
 @unittest.skipUnless(support.is_emscripten, "only available on Emscripten")
 deftest_emscripten_info(self):
 self.assertEqual(len(sys._emscripten_info), 4)

Misc/NEWS.d/next/Core_and_Builtins/2025-08-06-16-55-44.gh-issue-133143.l7CI9v.rst

@@ -0,0 +1 @@
+Add ``sys.abi_info`` object to make ABI information more easily accessible.

Python/sysmodule.c

@@ -3268,6 +3268,7 @@ PyDoc_STR(
 "\n\
 Static objects:\n\
 \n\
+abi_info -- Python ABI information.\n\
 builtin_module_names -- tuple of module names built into this interpreter\n\
 copyright -- copyright notice pertaining to this interpreter\n\
 exec_prefix -- prefix used to find the machine-specific Python library\n\
@@ -3638,6 +3639,73 @@ make_impl_info(PyObject *version_info)
 returnNULL;
 }
 
+
+staticPyObject*
+make_abi_info(void)
+{
+// New entries should be added when needed for a supported platform, or (for
+// enabling an unsupported one) by core dev consensus. Entries should be removed
+// following PEP 387.
+intres;
+PyObject*abi_info, *value, *ns;
+abi_info=PyDict_New();
+if (abi_info==NULL){
+ goto error;
+ }
+
+value=PyLong_FromLong(sizeof(void*) *8);
+if (value==NULL){
+ goto error;
+ }
+res=PyDict_SetItemString(abi_info, "pointer_bits", value);
+Py_DECREF(value);
+if (res<0){
+ goto error;
+ }
+
+#ifdefPy_GIL_DISABLED
+value=Py_True;
+#else
+value=Py_False;
+#endif
+res=PyDict_SetItemString(abi_info, "free_threaded", value);
+if (res<0){
+ goto error;
+ }
+
+#ifdefPy_DEBUG
+value=Py_True;
+#else
+value=Py_False;
+#endif
+res=PyDict_SetItemString(abi_info, "debug", value);
+if (res<0){
+ goto error;
+ }
+
+#ifPY_BIG_ENDIAN
+value=PyUnicode_FromString("big");
+#else
+value=PyUnicode_FromString("little");
+#endif
+if (value==NULL){
+ goto error;
+ }
+res=PyDict_SetItemString(abi_info, "byteorder", value);
+Py_DECREF(value);
+if (res<0){
+ goto error;
+ }
+
+ns=_PyNamespace_New(abi_info);
+Py_DECREF(abi_info);
+returnns;
+
+error:
+Py_DECREF(abi_info);
+returnNULL;
+}
+
 #ifdef__EMSCRIPTEN__
 
 PyDoc_STRVAR(emscripten_info__doc__,
@@ -3863,6 +3931,8 @@ _PySys_InitCore(PyThreadState *tstate, PyObject *sysdict)
 
 SET_SYS("thread_info", PyThread_GetInfo());
 
+SET_SYS("abi_info", make_abi_info());
+
 /* initialize asyncgen_hooks */
 if (_PyStructSequence_InitBuiltin(interp, &AsyncGenHooksType,
 &asyncgen_hooks_desc) <0)