Skip to content

gh-121647: Prefer decltype() for _Py_TYPEOF() on C++ #157267

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
vstinner merged 4 commits into from
Sep 10, 2026
+10 −7
Merged

gh-121647: Prefer decltype() for _Py_TYPEOF() on C++ #157267

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
85a6ba9
gh-121647: Prefer decltype() for _Py_TYPEOF() on C++
vstinner Sep 10, 2026
13de0a0
Use _MSVC_LANG macro
vstinner Sep 10, 2026
ae56459
Fix Py_CLEAR/Py_SETREF macros for C++
vstinner Sep 10, 2026
dec5373
Use Chris's suggestion
vstinner Sep 10, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 2 additions & 2 deletions Include/cpython/object.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -352,7 +352,7 @@ PyAPI_FUNC(PyObject *) _PyObject_FunctionStr(PyObject *);
#ifdef _Py_TYPEOF
#define Py_SETREF(dst, src) \
do { \
_Py_TYPEOF(dst)* _tmp_dst_ptr = &(dst); \
_Py_TYPEOF(&(dst)) _tmp_dst_ptr = &(dst); \
_Py_TYPEOF(dst) _tmp_old_dst = (*_tmp_dst_ptr); \
*_tmp_dst_ptr = (src); \
Py_DECREF(_tmp_old_dst); \
Expand All @@ -374,7 +374,7 @@ PyAPI_FUNC(PyObject *) _PyObject_FunctionStr(PyObject *);
#ifdef _Py_TYPEOF
#define Py_XSETREF(dst, src) \
do { \
_Py_TYPEOF(dst)* _tmp_dst_ptr = &(dst); \
_Py_TYPEOF(&(dst)) _tmp_dst_ptr = &(dst); \
_Py_TYPEOF(dst) _tmp_old_dst = (*_tmp_dst_ptr); \
*_tmp_dst_ptr = (src); \
Py_XDECREF(_tmp_old_dst); \
Expand Down
11 changes: 7 additions & 4 deletions Include/pyport.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -538,15 +538,18 @@ extern "C" {
//
// Example: _Py_TYPEOF(x) x_copy = (x);
//
// On C23, use typeof(). Otherwise __typeof__() if on GCC, clang or
// MSVC 17.9 and newer. Else if on C++11 or newer, decltype() is used.
// On C23, use typeof(). On C++11, use decltype(). Otherwise, use __typeof__()
// if on GCC, clang or MSVC 17.9 and newer.
//
// On MSVC, check also _MSVC_LANG since __cplusplus is 199711L unless
// the /Zc:__cplusplus flag is used.
#if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 202311L
# define _Py_TYPEOF(expr) typeof(expr)
#elif defined(__cplusplus) && (__cplusplus >= 201103L || _MSVC_LANG >= 201103L)
# define _Py_TYPEOF(expr) decltype(expr)
#elif defined(__GNUC__) || defined(__clang__) || \
(defined(_MSC_VER) && _MSC_VER >= 1939)
# define _Py_TYPEOF(expr) __typeof__(expr)
#elif defined(__cplusplus) && __cplusplus >= 201103L
# define _Py_TYPEOF(expr) decltype(expr)
#endif


Expand Down
2 changes: 1 addition & 1 deletion Include/refcount.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -482,7 +482,7 @@ static inline Py_ALWAYS_INLINE void Py_DECREF(PyObject *op)
#ifdef _Py_TYPEOF
#define Py_CLEAR(op) \
do { \
_Py_TYPEOF(op)* _tmp_op_ptr = &(op); \
_Py_TYPEOF(&(op)) _tmp_op_ptr = &(op); \
_Py_TYPEOF(op) _tmp_old_op = (*_tmp_op_ptr); \
if (_tmp_old_op != _Py_NULL) { \
*_tmp_op_ptr = _Py_NULL; \
Expand Down
Loading