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Diffstat (limited to 'Doc/using')
| -rw-r--r-- | Doc/using/configure.rst | 43 |
1 files changed, 24 insertions, 19 deletions
diff --git a/Doc/using/configure.rst b/Doc/using/configure.rst index e7fad7f2e6..4f3953ea5d 100644 --- a/Doc/using/configure.rst +++ b/Doc/using/configure.rst @@ -208,43 +208,48 @@ recommended for best performance. .. _debug-build: -Debug build ------------ +Python Debug Build +------------------ A debug build is Python built with the :option:`--with-pydebug` configure option. Effects of a debug build: -* Define ``Py_DEBUG`` and ``Py_REF_DEBUG`` macros. +* Display all warnings by default: the list of default warning filters is empty + in the :mod:`warnings` module. * Add ``d`` to :data:`sys.abiflags`. * Add :func:`sys.gettotalrefcount` function. * Add :option:`-X showrefcount <-X>` command line option. * Add :envvar:`PYTHONTHREADDEBUG` environment variable. * Add support for the ``__ltrace__`` variable: enable low-level tracing in the bytecode evaluation loop if the variable is defined. -* The list of default warning filters is empty in the :mod:`warnings` module. -* Install debug hooks on memory allocators to detect buffer overflow and other - memory errors: see :c:func:`PyMem_SetupDebugHooks`. -* Build Python with assertions (don't set ``NDEBUG`` macro): - ``assert(...);`` and ``_PyObject_ASSERT(...);``. - See also the :option:`--with-assertions` configure option. -* Unicode and int objects are created with their memory filled with a pattern - to help detecting uninitialized bytes. -* Many functions ensure that are not called with an exception raised, since - they can clear or replace the current exception. -* The garbage collector (:func:`gc.collect` function) runs some basic checks on - objects consistency. -* More generally, add runtime checks, code surroundeded by ``#ifdef Py_DEBUG`` - and ``#endif``. +* Install :ref:`debug hooks on memory allocators <default-memory-allocators>` + to detect buffer overflow and other memory errors. +* Define ``Py_DEBUG`` and ``Py_REF_DEBUG`` macros. +* Add runtime checks: code surroundeded by ``#ifdef Py_DEBUG`` and ``#endif``. + Enable ``assert(...)`` and ``_PyObject_ASSERT(...)`` assertions: don't set + the ``NDEBUG`` macro (see also the :option:`--with-assertions` configure + option). Main runtime checks: + + * Add sanity checks on the function arguments. + * Unicode and int objects are created with their memory filled with a pattern + to detect usage of uninitialized objects. + * Ensure that functions which can clear or replace the current exception are + not called with an exception raised. + * The garbage collector (:func:`gc.collect` function) runs some basic checks + on objects consistency. + * The :c:macro:`Py_SAFE_DOWNCAST()` macro checks for integer underflow and + overflow when downcasting from wide types to narrow types. See also the :ref:`Python Development Mode <devmode>` and the :option:`--with-trace-refs` configure option. .. versionchanged:: 3.8 Release builds and debug builds are now ABI compatible: defining the - ``Py_DEBUG`` macro no longer implies the ``Py_TRACE_REFS`` macro, which - introduces the only ABI incompatibility. + ``Py_DEBUG`` macro no longer implies the ``Py_TRACE_REFS`` macro (see the + :option:`--with-trace-refs` option), which introduces the only ABI + incompatibility. Debug options |