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Diffstat (limited to 'Doc/whatsnew/3.6.rst')
| -rw-r--r-- | Doc/whatsnew/3.6.rst | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/Doc/whatsnew/3.6.rst b/Doc/whatsnew/3.6.rst index 3afe2d4..588826b 100644 --- a/Doc/whatsnew/3.6.rst +++ b/Doc/whatsnew/3.6.rst @@ -80,6 +80,9 @@ Summary -- Release highlights PEP written by Carl Meyer +New Features +============ + .. _whatsnew-fstrings: PEP 498: Formatted string literals @@ -98,6 +101,34 @@ evaluated at run time, and then formatted using the :func:`format` protocol. See :pep:`498` and the main documentation at :ref:`f-strings`. +PYTHONMALLOC environment variable +--------------------------------- + +The new :envvar:`PYTHONMALLOC` environment variable allows to set the Python +memory allocators and/or install debug hooks. + +It is now possible to install debug hooks on Python memory allocators on Python +compiled in release mode using ``PYTHONMALLOC=debug``. Effects of debug hooks: + +* Newly allocated memory is filled with the byte ``0xCB`` +* Freed memory is filled with the byte ``0xDB`` +* Detect violations of Python memory allocator API. For example, + :c:func:`PyObject_Free` called on a memory block allocated by + :c:func:`PyMem_Malloc`. +* Detect write before the start of the buffer (buffer underflow) +* Detect write after the end of the buffer (buffer overflow) + +See the :c:func:`PyMem_SetupDebugHooks` function for debug hooks on Python +memory allocators. + +It is now also possible to force the usage of the :c:func:`malloc` allocator of +the C library for all Python memory allocations using ``PYTHONMALLOC=malloc``. +It helps to use external memory debuggers like Valgrind on a Python compiled in +release mode. + +(Contributed by Victor Stinner in :issue:`26516`.) + + Other Language Changes ====================== |