gh-143869: Add PEP 757 functions to the limited API

Include/cpython/longintrepr.h

@@ -138,45 +138,6 @@ _PyLong_CompactValue(const PyLongObject *op)
 
 #define PyUnstable_Long_CompactValue _PyLong_CompactValue
 
-
-/* --- Import/Export API -------------------------------------------------- */
-
-typedef struct PyLongLayout {
-    uint8_t bits_per_digit;
-    uint8_t digit_size;
-    int8_t digits_order;
-    int8_t digit_endianness;
-} PyLongLayout;
-
-PyAPI_FUNC(const PyLongLayout*) PyLong_GetNativeLayout(void);
-
-typedef struct PyLongExport {
-    int64_t value;
-    uint8_t negative;
-    Py_ssize_t ndigits;
-    const void *digits;
-    // Member used internally, must not be used for other purpose.
-    Py_uintptr_t _reserved;
-} PyLongExport;
-
-PyAPI_FUNC(int) PyLong_Export(
-    PyObject *obj,
-    PyLongExport *export_long);
-PyAPI_FUNC(void) PyLong_FreeExport(
-    PyLongExport *export_long);
-
-
-/* --- PyLongWriter API --------------------------------------------------- */
-
-typedef struct PyLongWriter PyLongWriter;
-
-PyAPI_FUNC(PyLongWriter*) PyLongWriter_Create(
-    int negative,
-    Py_ssize_t ndigits,
-    void **digits);
-PyAPI_FUNC(PyObject*) PyLongWriter_Finish(PyLongWriter *writer);
-PyAPI_FUNC(void) PyLongWriter_Discard(PyLongWriter *writer);
-
 #ifdef __cplusplus
 }
 #endif

Include/longobject.h

@@ -166,6 +166,44 @@ PyAPI_FUNC(PyObject *) PyLong_FromString(const char *, char **, int);
 PyAPI_FUNC(unsigned long) PyOS_strtoul(const char *, char **, int);
 PyAPI_FUNC(long) PyOS_strtol(const char *, char **, int);
 
+/* --- Import/Export API -------------------------------------------------- */
+
+typedef struct PyLongLayout {
+    uint8_t bits_per_digit;
+    uint8_t digit_size;
+    int8_t digits_order;
+    int8_t digit_endianness;
+} PyLongLayout;
+
+PyAPI_FUNC(const PyLongLayout*) PyLong_GetNativeLayout(void);
+
+typedef struct PyLongExport {
+    int64_t value;
+    uint8_t negative;
+    Py_ssize_t ndigits;
+    const void *digits;
+    // Member used internally, must not be used for other purpose.
+    Py_uintptr_t _reserved;
+} PyLongExport;
+
+PyAPI_FUNC(int) PyLong_Export(
+    PyObject *obj,
+    PyLongExport *export_long);
+PyAPI_FUNC(void) PyLong_FreeExport(
+    PyLongExport *export_long);
+
+
+/* --- PyLongWriter API --------------------------------------------------- */
+
+typedef struct PyLongWriter PyLongWriter;
+
+PyAPI_FUNC(PyLongWriter*) PyLongWriter_Create(
+    int negative,
+    Py_ssize_t ndigits,
+    void **digits);
+PyAPI_FUNC(PyObject*) PyLongWriter_Finish(PyLongWriter *writer);
+PyAPI_FUNC(void) PyLongWriter_Discard(PyLongWriter *writer);
+
 #ifndef Py_LIMITED_API
 #  define Py_CPYTHON_LONGOBJECT_H
 #  include "cpython/longobject.h"

Misc/NEWS.d/next/C_API/2026-01-16-15-04-26.gh-issue-143869.vf94km.rst

@@ -0,0 +1,5 @@
+Added :c:func:`PyLong_GetNativeLayout`, :c:struct:`PyLongLayout`,
+:c:struct:`PyLongExport`, :c:func:`PyLong_Export`,
+:c:func:`PyLong_FreeExport`, :c:struct:`PyLongWriter`,
+:c:func:`PyLongWriter_Create`, :c:func:`PyLongWriter_Finish` and
+:c:func:`PyLongWriter_Discard` to the limited API.

Misc/stable_abi.toml

@@ -2664,3 +2664,24 @@
 [function.Py_SET_SIZE]
     # Before 3.15, this was a macro that accessed the PyObject member
     added = '3.15'
+[function.PyLong_GetNativeLayout]
+    added = '3.15'
+[function.PyLong_Export]
+    added = '3.15'
+[function.PyLong_FreeExport]
+    added = '3.15'
+[function.PyLongWriter_Create]
+    added = '3.15'
+[function.PyLongWriter_Finish]
+    added = '3.15'
+[function.PyLongWriter_Discard]
+    added = '3.15'
+[struct.PyLongWriter]
+    added = '3.15'
+    struct_abi_kind = 'opaque'
+[struct.PyLongLayout]
+    added = '3.15'
+    struct_abi_kind = 'full-abi'
+[struct.PyLongExport]
+    added = '3.15'
+    struct_abi_kind = 'members'