mirror of https://github.com/python/cpython
1057 lines
32 KiB
ReStructuredText
1057 lines
32 KiB
ReStructuredText
.. highlight:: c
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.. _init-config:
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***********************************
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Python Initialization Configuration
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***********************************
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.. versionadded:: 3.8
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Structures:
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* :c:type:`PyConfig`
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* :c:type:`PyPreConfig`
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* :c:type:`PyStatus`
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* :c:type:`PyWideStringList`
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Functions:
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* :c:func:`PyConfig_Clear`
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* :c:func:`PyConfig_InitIsolatedConfig`
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* :c:func:`PyConfig_InitPythonConfig`
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* :c:func:`PyConfig_Read`
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* :c:func:`PyConfig_SetArgv`
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* :c:func:`PyConfig_SetBytesArgv`
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* :c:func:`PyConfig_SetBytesString`
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* :c:func:`PyConfig_SetString`
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* :c:func:`PyConfig_SetWideStringList`
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* :c:func:`PyPreConfig_InitIsolatedConfig`
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* :c:func:`PyPreConfig_InitPythonConfig`
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* :c:func:`PyStatus_Error`
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* :c:func:`PyStatus_Exception`
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* :c:func:`PyStatus_Exit`
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* :c:func:`PyStatus_IsError`
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* :c:func:`PyStatus_IsExit`
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* :c:func:`PyStatus_NoMemory`
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* :c:func:`PyStatus_Ok`
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* :c:func:`PyWideStringList_Append`
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* :c:func:`PyWideStringList_Insert`
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* :c:func:`Py_ExitStatusException`
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* :c:func:`Py_InitializeFromConfig`
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* :c:func:`Py_PreInitialize`
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* :c:func:`Py_PreInitializeFromArgs`
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* :c:func:`Py_PreInitializeFromBytesArgs`
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* :c:func:`Py_RunMain`
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The preconfiguration (``PyPreConfig`` type) is stored in
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``_PyRuntime.preconfig`` and the configuration (``PyConfig`` type) is stored in
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``PyInterpreterState.config``.
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See also :ref:`Initialization, Finalization, and Threads <initialization>`.
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.. seealso::
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:pep:`587` "Python Initialization Configuration".
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PyWideStringList
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----------------
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.. c:type:: PyWideStringList
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List of ``wchar_t*`` strings.
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If *length* is non-zero, *items* must be non-``NULL`` and all strings must be
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non-``NULL``.
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Methods:
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.. c:function:: PyStatus PyWideStringList_Append(PyWideStringList *list, const wchar_t *item)
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Append *item* to *list*.
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Python must be preinitialized to call this function.
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.. c:function:: PyStatus PyWideStringList_Insert(PyWideStringList *list, Py_ssize_t index, const wchar_t *item)
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Insert *item* into *list* at *index*.
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If *index* is greater than or equal to *list* length, append *item* to
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*list*.
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*index* must be greater than or equal to 0.
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Python must be preinitialized to call this function.
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Structure fields:
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.. c:member:: Py_ssize_t length
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List length.
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.. c:member:: wchar_t** items
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List items.
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PyStatus
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--------
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.. c:type:: PyStatus
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Structure to store an initialization function status: success, error
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or exit.
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For an error, it can store the C function name which created the error.
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Structure fields:
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.. c:member:: int exitcode
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Exit code. Argument passed to ``exit()``.
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.. c:member:: const char *err_msg
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Error message.
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.. c:member:: const char *func
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Name of the function which created an error, can be ``NULL``.
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Functions to create a status:
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.. c:function:: PyStatus PyStatus_Ok(void)
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Success.
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.. c:function:: PyStatus PyStatus_Error(const char *err_msg)
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Initialization error with a message.
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.. c:function:: PyStatus PyStatus_NoMemory(void)
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Memory allocation failure (out of memory).
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.. c:function:: PyStatus PyStatus_Exit(int exitcode)
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Exit Python with the specified exit code.
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Functions to handle a status:
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.. c:function:: int PyStatus_Exception(PyStatus status)
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Is the status an error or an exit? If true, the exception must be
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handled; by calling :c:func:`Py_ExitStatusException` for example.
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.. c:function:: int PyStatus_IsError(PyStatus status)
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Is the result an error?
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.. c:function:: int PyStatus_IsExit(PyStatus status)
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Is the result an exit?
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.. c:function:: void Py_ExitStatusException(PyStatus status)
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Call ``exit(exitcode)`` if *status* is an exit. Print the error
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message and exit with a non-zero exit code if *status* is an error. Must
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only be called if ``PyStatus_Exception(status)`` is non-zero.
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.. note::
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Internally, Python uses macros which set ``PyStatus.func``,
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whereas functions to create a status set ``func`` to ``NULL``.
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Example::
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PyStatus alloc(void **ptr, size_t size)
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{
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*ptr = PyMem_RawMalloc(size);
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if (*ptr == NULL) {
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return PyStatus_NoMemory();
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}
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return PyStatus_Ok();
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}
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int main(int argc, char **argv)
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{
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void *ptr;
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PyStatus status = alloc(&ptr, 16);
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if (PyStatus_Exception(status)) {
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Py_ExitStatusException(status);
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}
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PyMem_Free(ptr);
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return 0;
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}
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PyPreConfig
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-----------
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.. c:type:: PyPreConfig
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Structure used to preinitialize Python:
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* Set the Python memory allocator
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* Configure the LC_CTYPE locale
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* Set the UTF-8 mode
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Function to initialize a preconfiguration:
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.. c:function:: void PyPreConfig_InitIsolatedConfig(PyPreConfig *preconfig)
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Initialize the preconfiguration with :ref:`Python Configuration
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<init-python-config>`.
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.. c:function:: void PyPreConfig_InitPythonConfig(PyPreConfig *preconfig)
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Initialize the preconfiguration with :ref:`Isolated Configuration
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<init-isolated-conf>`.
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Structure fields:
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.. c:member:: int allocator
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Name of the memory allocator:
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* ``PYMEM_ALLOCATOR_NOT_SET`` (``0``): don't change memory allocators
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(use defaults)
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* ``PYMEM_ALLOCATOR_DEFAULT`` (``1``): default memory allocators
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* ``PYMEM_ALLOCATOR_DEBUG`` (``2``): default memory allocators with
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debug hooks
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* ``PYMEM_ALLOCATOR_MALLOC`` (``3``): force usage of ``malloc()``
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* ``PYMEM_ALLOCATOR_MALLOC_DEBUG`` (``4``): force usage of
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``malloc()`` with debug hooks
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* ``PYMEM_ALLOCATOR_PYMALLOC`` (``5``): :ref:`Python pymalloc memory
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allocator <pymalloc>`
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* ``PYMEM_ALLOCATOR_PYMALLOC_DEBUG`` (``6``): :ref:`Python pymalloc
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memory allocator <pymalloc>` with debug hooks
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``PYMEM_ALLOCATOR_PYMALLOC`` and ``PYMEM_ALLOCATOR_PYMALLOC_DEBUG``
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are not supported if Python is configured using ``--without-pymalloc``
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See :ref:`Memory Management <memory>`.
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.. c:member:: int configure_locale
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Set the LC_CTYPE locale to the user preferred locale? If equals to 0, set
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:c:member:`coerce_c_locale` and :c:member:`coerce_c_locale_warn` to 0.
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.. c:member:: int coerce_c_locale
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If equals to 2, coerce the C locale; if equals to 1, read the LC_CTYPE
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locale to decide if it should be coerced.
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.. c:member:: int coerce_c_locale_warn
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If non-zero, emit a warning if the C locale is coerced.
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.. c:member:: int dev_mode
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See :c:member:`PyConfig.dev_mode`.
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.. c:member:: int isolated
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See :c:member:`PyConfig.isolated`.
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.. c:member:: int legacy_windows_fs_encoding (Windows only)
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If non-zero, disable UTF-8 Mode, set the Python filesystem encoding to
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``mbcs``, set the filesystem error handler to ``replace``.
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Only available on Windows. ``#ifdef MS_WINDOWS`` macro can be used for
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Windows specific code.
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.. c:member:: int parse_argv
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If non-zero, :c:func:`Py_PreInitializeFromArgs` and
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:c:func:`Py_PreInitializeFromBytesArgs` parse their ``argv`` argument the
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same way the regular Python parses command line arguments: see
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:ref:`Command Line Arguments <using-on-cmdline>`.
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.. c:member:: int use_environment
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See :c:member:`PyConfig.use_environment`.
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.. c:member:: int utf8_mode
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If non-zero, enable the UTF-8 mode.
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Preinitialization with PyPreConfig
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----------------------------------
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Functions to preinitialize Python:
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.. c:function:: PyStatus Py_PreInitialize(const PyPreConfig *preconfig)
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Preinitialize Python from *preconfig* preconfiguration.
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.. c:function:: PyStatus Py_PreInitializeFromBytesArgs(const PyPreConfig *preconfig, int argc, char * const *argv)
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Preinitialize Python from *preconfig* preconfiguration and command line
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arguments (bytes strings).
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.. c:function:: PyStatus Py_PreInitializeFromArgs(const PyPreConfig *preconfig, int argc, wchar_t * const * argv)
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Preinitialize Python from *preconfig* preconfiguration and command line
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arguments (wide strings).
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The caller is responsible to handle exceptions (error or exit) using
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:c:func:`PyStatus_Exception` and :c:func:`Py_ExitStatusException`.
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For :ref:`Python Configuration <init-python-config>`
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(:c:func:`PyPreConfig_InitPythonConfig`), if Python is initialized with
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command line arguments, the command line arguments must also be passed to
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preinitialize Python, since they have an effect on the pre-configuration
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like encodings. For example, the :option:`-X utf8 <-X>` command line option
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enables the UTF-8 Mode.
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``PyMem_SetAllocator()`` can be called after :c:func:`Py_PreInitialize` and
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before :c:func:`Py_InitializeFromConfig` to install a custom memory allocator.
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It can be called before :c:func:`Py_PreInitialize` if
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:c:member:`PyPreConfig.allocator` is set to ``PYMEM_ALLOCATOR_NOT_SET``.
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Python memory allocation functions like :c:func:`PyMem_RawMalloc` must not be
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used before Python preinitialization, whereas calling directly ``malloc()`` and
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``free()`` is always safe. :c:func:`Py_DecodeLocale` must not be called before
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the preinitialization.
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Example using the preinitialization to enable the UTF-8 Mode::
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PyStatus status;
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PyPreConfig preconfig;
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PyPreConfig_InitPythonConfig(&preconfig);
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preconfig.utf8_mode = 1;
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status = Py_PreInitialize(&preconfig);
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if (PyStatus_Exception(status)) {
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Py_ExitStatusException(status);
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}
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/* at this point, Python will speak UTF-8 */
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Py_Initialize();
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/* ... use Python API here ... */
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Py_Finalize();
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PyConfig
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--------
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.. c:type:: PyConfig
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Structure containing most parameters to configure Python.
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Structure methods:
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.. c:function:: void PyConfig_InitPythonConfig(PyConfig *config)
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Initialize configuration with :ref:`Python Configuration
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<init-python-config>`.
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.. c:function:: void PyConfig_InitIsolatedConfig(PyConfig *config)
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Initialize configuration with :ref:`Isolated Configuration
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<init-isolated-conf>`.
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.. c:function:: PyStatus PyConfig_SetString(PyConfig *config, wchar_t * const *config_str, const wchar_t *str)
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Copy the wide character string *str* into ``*config_str``.
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Preinitialize Python if needed.
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.. c:function:: PyStatus PyConfig_SetBytesString(PyConfig *config, wchar_t * const *config_str, const char *str)
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Decode *str* using ``Py_DecodeLocale()`` and set the result into ``*config_str``.
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Preinitialize Python if needed.
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.. c:function:: PyStatus PyConfig_SetArgv(PyConfig *config, int argc, wchar_t * const *argv)
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Set command line arguments from wide character strings.
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Preinitialize Python if needed.
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.. c:function:: PyStatus PyConfig_SetBytesArgv(PyConfig *config, int argc, char * const *argv)
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Set command line arguments: decode bytes using :c:func:`Py_DecodeLocale`.
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Preinitialize Python if needed.
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.. c:function:: PyStatus PyConfig_SetWideStringList(PyConfig *config, PyWideStringList *list, Py_ssize_t length, wchar_t **items)
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Set the list of wide strings *list* to *length* and *items*.
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Preinitialize Python if needed.
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.. c:function:: PyStatus PyConfig_Read(PyConfig *config)
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Read all Python configuration.
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Fields which are already initialized are left unchanged.
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Preinitialize Python if needed.
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.. c:function:: void PyConfig_Clear(PyConfig *config)
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Release configuration memory.
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Most ``PyConfig`` methods preinitialize Python if needed. In that case, the
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Python preinitialization configuration in based on the :c:type:`PyConfig`.
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If configuration fields which are in common with :c:type:`PyPreConfig` are
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tuned, they must be set before calling a :c:type:`PyConfig` method:
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* :c:member:`~PyConfig.dev_mode`
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* :c:member:`~PyConfig.isolated`
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* :c:member:`~PyConfig.parse_argv`
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* :c:member:`~PyConfig.use_environment`
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Moreover, if :c:func:`PyConfig_SetArgv` or :c:func:`PyConfig_SetBytesArgv`
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is used, this method must be called first, before other methods, since the
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preinitialization configuration depends on command line arguments (if
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:c:member:`parse_argv` is non-zero).
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The caller of these methods is responsible to handle exceptions (error or
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exit) using ``PyStatus_Exception()`` and ``Py_ExitStatusException()``.
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Structure fields:
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.. c:member:: PyWideStringList argv
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Command line arguments, :data:`sys.argv`. See
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:c:member:`~PyConfig.parse_argv` to parse :c:member:`~PyConfig.argv` the
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same way the regular Python parses Python command line arguments. If
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:c:member:`~PyConfig.argv` is empty, an empty string is added to ensure
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that :data:`sys.argv` always exists and is never empty.
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.. c:member:: wchar_t* base_exec_prefix
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:data:`sys.base_exec_prefix`.
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.. c:member:: wchar_t* base_executable
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:data:`sys._base_executable`: ``__PYVENV_LAUNCHER__`` environment
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variable value, or copy of :c:member:`PyConfig.executable`.
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.. c:member:: wchar_t* base_prefix
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:data:`sys.base_prefix`.
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.. c:member:: int buffered_stdio
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If equals to 0, enable unbuffered mode, making the stdout and stderr
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streams unbuffered.
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stdin is always opened in buffered mode.
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.. c:member:: int bytes_warning
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If equals to 1, issue a warning when comparing :class:`bytes` or
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:class:`bytearray` with :class:`str`, or comparing :class:`bytes` with
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:class:`int`. If equal or greater to 2, raise a :exc:`BytesWarning`
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exception.
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.. c:member:: wchar_t* check_hash_pycs_mode
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Control the validation behavior of hash-based ``.pyc`` files (see
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:pep:`552`): :option:`--check-hash-based-pycs` command line option value.
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Valid values: ``always``, ``never`` and ``default``.
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The default value is: ``default``.
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.. c:member:: int configure_c_stdio
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If non-zero, configure C standard streams (``stdio``, ``stdout``,
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``stdout``). For example, set their mode to ``O_BINARY`` on Windows.
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.. c:member:: int dev_mode
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Development mode: see :option:`-X dev <-X>`.
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.. c:member:: int dump_refs
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If non-zero, dump all objects which are still alive at exit.
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Require a debug build of Python (``Py_REF_DEBUG`` macro must be defined).
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.. c:member:: wchar_t* exec_prefix
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:data:`sys.exec_prefix`.
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.. c:member:: wchar_t* executable
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:data:`sys.executable`.
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.. c:member:: int faulthandler
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If non-zero, call :func:`faulthandler.enable` at startup.
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.. c:member:: wchar_t* filesystem_encoding
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Filesystem encoding, :func:`sys.getfilesystemencoding`.
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.. c:member:: wchar_t* filesystem_errors
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Filesystem encoding errors, :func:`sys.getfilesystemencodeerrors`.
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.. c:member:: unsigned long hash_seed
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.. c:member:: int use_hash_seed
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Randomized hash function seed.
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If :c:member:`~PyConfig.use_hash_seed` is zero, a seed is chosen randomly
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at Pythonstartup, and :c:member:`~PyConfig.hash_seed` is ignored.
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.. c:member:: wchar_t* home
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Python home directory.
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Initialized from :envvar:`PYTHONHOME` environment variable value by
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default.
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.. c:member:: int import_time
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If non-zero, profile import time.
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.. c:member:: int inspect
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Enter interactive mode after executing a script or a command.
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.. c:member:: int install_signal_handlers
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Install signal handlers?
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.. c:member:: int interactive
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Interactive mode.
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.. c:member:: int isolated
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If greater than 0, enable isolated mode:
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* :data:`sys.path` contains neither the script's directory (computed from
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``argv[0]`` or the current directory) nor the user's site-packages
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directory.
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* Python REPL doesn't import :mod:`readline` nor enable default readline
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configuration on interactive prompts.
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* Set :c:member:`~PyConfig.use_environment` and
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:c:member:`~PyConfig.user_site_directory` to 0.
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.. c:member:: int legacy_windows_stdio
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If non-zero, use :class:`io.FileIO` instead of
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:class:`io.WindowsConsoleIO` for :data:`sys.stdin`, :data:`sys.stdout`
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and :data:`sys.stderr`.
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Only available on Windows. ``#ifdef MS_WINDOWS`` macro can be used for
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|
Windows specific code.
|
|
|
|
.. c:member:: int malloc_stats
|
|
|
|
If non-zero, dump statistics on :ref:`Python pymalloc memory allocator
|
|
<pymalloc>` at exit.
|
|
|
|
The option is ignored if Python is built using ``--without-pymalloc``.
|
|
|
|
.. c:member:: wchar_t* pythonpath_env
|
|
|
|
Module search paths as a string separated by ``DELIM``
|
|
(:data:`os.path.pathsep`).
|
|
|
|
Initialized from :envvar:`PYTHONPATH` environment variable value by
|
|
default.
|
|
|
|
.. c:member:: PyWideStringList module_search_paths
|
|
.. c:member:: int module_search_paths_set
|
|
|
|
:data:`sys.path`. If :c:member:`~PyConfig.module_search_paths_set` is
|
|
equal to 0, the :c:member:`~PyConfig.module_search_paths` is overridden
|
|
by the function calculating the :ref:`Path Configuration
|
|
<init-path-config>`.
|
|
|
|
.. c:member:: int optimization_level
|
|
|
|
Compilation optimization level:
|
|
|
|
* 0: Peephole optimizer (and ``__debug__`` is set to ``True``)
|
|
* 1: Remove assertions, set ``__debug__`` to ``False``
|
|
* 2: Strip docstrings
|
|
|
|
.. c:member:: int parse_argv
|
|
|
|
If non-zero, parse :c:member:`~PyConfig.argv` the same way the regular
|
|
Python command line arguments, and strip Python arguments from
|
|
:c:member:`~PyConfig.argv`: see :ref:`Command Line Arguments
|
|
<using-on-cmdline>`.
|
|
|
|
.. c:member:: int parser_debug
|
|
|
|
If non-zero, turn on parser debugging output (for expert only, depending
|
|
on compilation options).
|
|
|
|
.. c:member:: int pathconfig_warnings
|
|
|
|
If equal to 0, suppress warnings when calculating the :ref:`Path
|
|
Configuration <init-path-config>` (Unix only, Windows does not log any
|
|
warning). Otherwise, warnings are written into ``stderr``.
|
|
|
|
.. c:member:: wchar_t* prefix
|
|
|
|
:data:`sys.prefix`.
|
|
|
|
.. c:member:: wchar_t* program_name
|
|
|
|
Program name. Used to initialize :c:member:`~PyConfig.executable`, and in
|
|
early error messages.
|
|
|
|
.. c:member:: wchar_t* pycache_prefix
|
|
|
|
:data:`sys.pycache_prefix`: ``.pyc`` cache prefix.
|
|
|
|
If ``NULL``, :data:`sys.pycache_prefix` is set to ``None``.
|
|
|
|
.. c:member:: int quiet
|
|
|
|
Quiet mode. For example, don't display the copyright and version messages
|
|
in interactive mode.
|
|
|
|
.. c:member:: wchar_t* run_command
|
|
|
|
``python3 -c COMMAND`` argument. Used by :c:func:`Py_RunMain`.
|
|
|
|
.. c:member:: wchar_t* run_filename
|
|
|
|
``python3 FILENAME`` argument. Used by :c:func:`Py_RunMain`.
|
|
|
|
.. c:member:: wchar_t* run_module
|
|
|
|
``python3 -m MODULE`` argument. Used by :c:func:`Py_RunMain`.
|
|
|
|
.. c:member:: int show_alloc_count
|
|
|
|
Show allocation counts at exit?
|
|
|
|
Set to 1 by :option:`-X showalloccount <-X>` command line option.
|
|
|
|
Need a special Python build with ``COUNT_ALLOCS`` macro defined.
|
|
|
|
.. c:member:: int show_ref_count
|
|
|
|
Show total reference count at exit?
|
|
|
|
Set to 1 by :option:`-X showrefcount <-X>` command line option.
|
|
|
|
Need a debug build of Python (``Py_REF_DEBUG`` macro must be defined).
|
|
|
|
.. c:member:: int site_import
|
|
|
|
Import the :mod:`site` module at startup?
|
|
|
|
.. c:member:: int skip_source_first_line
|
|
|
|
Skip the first line of the source?
|
|
|
|
.. c:member:: wchar_t* stdio_encoding
|
|
.. c:member:: wchar_t* stdio_errors
|
|
|
|
Encoding and encoding errors of :data:`sys.stdin`, :data:`sys.stdout` and
|
|
:data:`sys.stderr`.
|
|
|
|
.. c:member:: int tracemalloc
|
|
|
|
If non-zero, call :func:`tracemalloc.start` at startup.
|
|
|
|
.. c:member:: int use_environment
|
|
|
|
If greater than 0, use :ref:`environment variables <using-on-envvars>`.
|
|
|
|
.. c:member:: int user_site_directory
|
|
|
|
If non-zero, add user site directory to :data:`sys.path`.
|
|
|
|
.. c:member:: int verbose
|
|
|
|
If non-zero, enable verbose mode.
|
|
|
|
.. c:member:: PyWideStringList warnoptions
|
|
|
|
:data:`sys.warnoptions`: options of the :mod:`warnings` module to build
|
|
warnings filters: lowest to highest priority.
|
|
|
|
The :mod:`warnings` module adds :data:`sys.warnoptions` in the reverse
|
|
order: the last :c:member:`PyConfig.warnoptions` item becomes the first
|
|
item of :data:`warnings.filters` which is checked first (highest
|
|
priority).
|
|
|
|
.. c:member:: int write_bytecode
|
|
|
|
If non-zero, write ``.pyc`` files.
|
|
|
|
:data:`sys.dont_write_bytecode` is initialized to the inverted value of
|
|
:c:member:`~PyConfig.write_bytecode`.
|
|
|
|
.. c:member:: PyWideStringList xoptions
|
|
|
|
:data:`sys._xoptions`.
|
|
|
|
If ``parse_argv`` is non-zero, ``argv`` arguments are parsed the same
|
|
way the regular Python parses command line arguments, and Python
|
|
arguments are stripped from ``argv``: see :ref:`Command Line Arguments
|
|
<using-on-cmdline>`.
|
|
|
|
The ``xoptions`` options are parsed to set other options: see :option:`-X`
|
|
option.
|
|
|
|
|
|
Initialization with PyConfig
|
|
----------------------------
|
|
|
|
Function to initialize Python:
|
|
|
|
.. c:function:: PyStatus Py_InitializeFromConfig(const PyConfig *config)
|
|
|
|
Initialize Python from *config* configuration.
|
|
|
|
The caller is responsible to handle exceptions (error or exit) using
|
|
:c:func:`PyStatus_Exception` and :c:func:`Py_ExitStatusException`.
|
|
|
|
If ``PyImport_FrozenModules``, ``PyImport_AppendInittab()`` or
|
|
``PyImport_ExtendInittab()`` are used, they must be set or called after Python
|
|
preinitialization and before the Python initialization.
|
|
|
|
Example setting the program name::
|
|
|
|
void init_python(void)
|
|
{
|
|
PyStatus status;
|
|
|
|
PyConfig config;
|
|
PyConfig_InitPythonConfig(&config);
|
|
|
|
/* Set the program name. Implicitly preinitialize Python. */
|
|
status = PyConfig_SetString(&config, &config.program_name,
|
|
L"/path/to/my_program");
|
|
if (PyStatus_Exception(status)) {
|
|
goto fail;
|
|
}
|
|
|
|
status = Py_InitializeFromConfig(&config);
|
|
if (PyStatus_Exception(status)) {
|
|
goto fail;
|
|
}
|
|
PyConfig_Clear(&config);
|
|
return;
|
|
|
|
fail:
|
|
PyConfig_Clear(&config);
|
|
Py_ExitStatusException(status);
|
|
}
|
|
|
|
More complete example modifying the default configuration, read the
|
|
configuration, and then override some parameters::
|
|
|
|
PyStatus init_python(const char *program_name)
|
|
{
|
|
PyStatus status;
|
|
|
|
PyConfig config;
|
|
PyConfig_InitPythonConfig(&config);
|
|
|
|
/* Set the program name before reading the configuration
|
|
(decode byte string from the locale encoding).
|
|
|
|
Implicitly preinitialize Python. */
|
|
status = PyConfig_SetBytesString(&config, &config.program_name,
|
|
program_name);
|
|
if (PyStatus_Exception(status)) {
|
|
goto done;
|
|
}
|
|
|
|
/* Read all configuration at once */
|
|
status = PyConfig_Read(&config);
|
|
if (PyStatus_Exception(status)) {
|
|
goto done;
|
|
}
|
|
|
|
/* Append our custom search path to sys.path */
|
|
status = PyWideStringList_Append(&config.module_search_paths,
|
|
L"/path/to/more/modules");
|
|
if (PyStatus_Exception(status)) {
|
|
goto done;
|
|
}
|
|
|
|
/* Override executable computed by PyConfig_Read() */
|
|
status = PyConfig_SetString(&config, &config.executable,
|
|
L"/path/to/my_executable");
|
|
if (PyStatus_Exception(status)) {
|
|
goto done;
|
|
}
|
|
|
|
status = Py_InitializeFromConfig(&config);
|
|
|
|
done:
|
|
PyConfig_Clear(&config);
|
|
return status;
|
|
}
|
|
|
|
|
|
.. _init-isolated-conf:
|
|
|
|
Isolated Configuration
|
|
----------------------
|
|
|
|
:c:func:`PyPreConfig_InitIsolatedConfig` and
|
|
:c:func:`PyConfig_InitIsolatedConfig` functions create a configuration to
|
|
isolate Python from the system. For example, to embed Python into an
|
|
application.
|
|
|
|
This configuration ignores global configuration variables, environments
|
|
variables, command line arguments (:c:member:`PyConfig.argv` is not parsed)
|
|
and user site directory. The C standard streams (ex: ``stdout``) and the
|
|
LC_CTYPE locale are left unchanged. Signal handlers are not installed.
|
|
|
|
Configuration files are still used with this configuration. Set the
|
|
:ref:`Path Configuration <init-path-config>` ("output fields") to ignore these
|
|
configuration files and avoid the function computing the default path
|
|
configuration.
|
|
|
|
|
|
.. _init-python-config:
|
|
|
|
Python Configuration
|
|
--------------------
|
|
|
|
:c:func:`PyPreConfig_InitPythonConfig` and :c:func:`PyConfig_InitPythonConfig`
|
|
functions create a configuration to build a customized Python which behaves as
|
|
the regular Python.
|
|
|
|
Environments variables and command line arguments are used to configure
|
|
Python, whereas global configuration variables are ignored.
|
|
|
|
This function enables C locale coercion (:pep:`538`) and UTF-8 Mode
|
|
(:pep:`540`) depending on the LC_CTYPE locale, :envvar:`PYTHONUTF8` and
|
|
:envvar:`PYTHONCOERCECLOCALE` environment variables.
|
|
|
|
Example of customized Python always running in isolated mode::
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
PyStatus status;
|
|
|
|
PyConfig config;
|
|
PyConfig_InitPythonConfig(&config);
|
|
config.isolated = 1;
|
|
|
|
/* Decode command line arguments.
|
|
Implicitly preinitialize Python (in isolated mode). */
|
|
status = PyConfig_SetBytesArgv(&config, argc, argv);
|
|
if (PyStatus_Exception(status)) {
|
|
goto fail;
|
|
}
|
|
|
|
status = Py_InitializeFromConfig(&config);
|
|
if (PyStatus_Exception(status)) {
|
|
goto fail;
|
|
}
|
|
PyConfig_Clear(&config);
|
|
|
|
return Py_RunMain();
|
|
|
|
fail:
|
|
PyConfig_Clear(&config);
|
|
if (PyStatus_IsExit(status)) {
|
|
return status.exitcode;
|
|
}
|
|
/* Display the error message and exit the process with
|
|
non-zero exit code */
|
|
Py_ExitStatusException(status);
|
|
}
|
|
|
|
|
|
.. _init-path-config:
|
|
|
|
Path Configuration
|
|
------------------
|
|
|
|
:c:type:`PyConfig` contains multiple fields for the path configuration:
|
|
|
|
* Path configuration inputs:
|
|
|
|
* :c:member:`PyConfig.home`
|
|
* :c:member:`PyConfig.pathconfig_warnings`
|
|
* :c:member:`PyConfig.program_name`
|
|
* :c:member:`PyConfig.pythonpath_env`
|
|
* current working directory: to get absolute paths
|
|
* ``PATH`` environment variable to get the program full path
|
|
(from :c:member:`PyConfig.program_name`)
|
|
* ``__PYVENV_LAUNCHER__`` environment variable
|
|
* (Windows only) Application paths in the registry under
|
|
"Software\Python\PythonCore\X.Y\PythonPath" of HKEY_CURRENT_USER and
|
|
HKEY_LOCAL_MACHINE (where X.Y is the Python version).
|
|
|
|
* Path configuration output fields:
|
|
|
|
* :c:member:`PyConfig.base_exec_prefix`
|
|
* :c:member:`PyConfig.base_executable`
|
|
* :c:member:`PyConfig.base_prefix`
|
|
* :c:member:`PyConfig.exec_prefix`
|
|
* :c:member:`PyConfig.executable`
|
|
* :c:member:`PyConfig.module_search_paths_set`,
|
|
:c:member:`PyConfig.module_search_paths`
|
|
* :c:member:`PyConfig.prefix`
|
|
|
|
If at least one "output field" is not set, Python calculates the path
|
|
configuration to fill unset fields. If
|
|
:c:member:`~PyConfig.module_search_paths_set` is equal to 0,
|
|
:c:member:`~PyConfig.module_search_paths` is overridden and
|
|
:c:member:`~PyConfig.module_search_paths_set` is set to 1.
|
|
|
|
It is possible to completely ignore the function calculating the default
|
|
path configuration by setting explicitly all path configuration output
|
|
fields listed above. A string is considered as set even if it is non-empty.
|
|
``module_search_paths`` is considered as set if
|
|
``module_search_paths_set`` is set to 1. In this case, path
|
|
configuration input fields are ignored as well.
|
|
|
|
Set :c:member:`~PyConfig.pathconfig_warnings` to 0 to suppress warnings when
|
|
calculating the path configuration (Unix only, Windows does not log any warning).
|
|
|
|
If :c:member:`~PyConfig.base_prefix` or :c:member:`~PyConfig.base_exec_prefix`
|
|
fields are not set, they inherit their value from :c:member:`~PyConfig.prefix`
|
|
and :c:member:`~PyConfig.exec_prefix` respectively.
|
|
|
|
:c:func:`Py_RunMain` and :c:func:`Py_Main` modify :data:`sys.path`:
|
|
|
|
* If :c:member:`~PyConfig.run_filename` is set and is a directory which contains a
|
|
``__main__.py`` script, prepend :c:member:`~PyConfig.run_filename` to
|
|
:data:`sys.path`.
|
|
* If :c:member:`~PyConfig.isolated` is zero:
|
|
|
|
* If :c:member:`~PyConfig.run_module` is set, prepend the current directory
|
|
to :data:`sys.path`. Do nothing if the current directory cannot be read.
|
|
* If :c:member:`~PyConfig.run_filename` is set, prepend the directory of the
|
|
filename to :data:`sys.path`.
|
|
* Otherwise, prepend an empty string to :data:`sys.path`.
|
|
|
|
If :c:member:`~PyConfig.site_import` is non-zero, :data:`sys.path` can be
|
|
modified by the :mod:`site` module. If
|
|
:c:member:`~PyConfig.user_site_directory` is non-zero and the user's
|
|
site-package directory exists, the :mod:`site` module appends the user's
|
|
site-package directory to :data:`sys.path`.
|
|
|
|
The following configuration files are used by the path configuration:
|
|
|
|
* ``pyvenv.cfg``
|
|
* ``python._pth`` (Windows only)
|
|
* ``pybuilddir.txt`` (Unix only)
|
|
|
|
The ``__PYVENV_LAUNCHER__`` environment variable is used to set
|
|
:c:member:`PyConfig.base_executable`
|
|
|
|
|
|
Py_RunMain()
|
|
------------
|
|
|
|
.. c:function:: int Py_RunMain(void)
|
|
|
|
Execute the command (:c:member:`PyConfig.run_command`), the script
|
|
(:c:member:`PyConfig.run_filename`) or the module
|
|
(:c:member:`PyConfig.run_module`) specified on the command line or in the
|
|
configuration.
|
|
|
|
By default and when if :option:`-i` option is used, run the REPL.
|
|
|
|
Finally, finalizes Python and returns an exit status that can be passed to
|
|
the ``exit()`` function.
|
|
|
|
See :ref:`Python Configuration <init-python-config>` for an example of
|
|
customized Python always running in isolated mode using
|
|
:c:func:`Py_RunMain`.
|
|
|
|
|
|
Multi-Phase Initialization Private Provisional API
|
|
--------------------------------------------------
|
|
|
|
This section is a private provisional API introducing multi-phase
|
|
initialization, the core feature of the :pep:`432`:
|
|
|
|
* "Core" initialization phase, "bare minimum Python":
|
|
|
|
* Builtin types;
|
|
* Builtin exceptions;
|
|
* Builtin and frozen modules;
|
|
* The :mod:`sys` module is only partially initialized
|
|
(ex: :data:`sys.path` doesn't exist yet).
|
|
|
|
* "Main" initialization phase, Python is fully initialized:
|
|
|
|
* Install and configure :mod:`importlib`;
|
|
* Apply the :ref:`Path Configuration <init-path-config>`;
|
|
* Install signal handlers;
|
|
* Finish :mod:`sys` module initialization (ex: create :data:`sys.stdout`
|
|
and :data:`sys.path`);
|
|
* Enable optional features like :mod:`faulthandler` and :mod:`tracemalloc`;
|
|
* Import the :mod:`site` module;
|
|
* etc.
|
|
|
|
Private provisional API:
|
|
|
|
* :c:member:`PyConfig._init_main`: if set to 0,
|
|
:c:func:`Py_InitializeFromConfig` stops at the "Core" initialization phase.
|
|
|
|
.. c:function:: PyStatus _Py_InitializeMain(void)
|
|
|
|
Move to the "Main" initialization phase, finish the Python initialization.
|
|
|
|
No module is imported during the "Core" phase and the ``importlib`` module is
|
|
not configured: the :ref:`Path Configuration <init-path-config>` is only
|
|
applied during the "Main" phase. It may allow to customize Python in Python to
|
|
override or tune the :ref:`Path Configuration <init-path-config>`, maybe
|
|
install a custom :data:`sys.meta_path` importer or an import hook, etc.
|
|
|
|
It may become possible to calculatin the :ref:`Path Configuration
|
|
<init-path-config>` in Python, after the Core phase and before the Main phase,
|
|
which is one of the :pep:`432` motivation.
|
|
|
|
The "Core" phase is not properly defined: what should be and what should
|
|
not be available at this phase is not specified yet. The API is marked
|
|
as private and provisional: the API can be modified or even be removed
|
|
anytime until a proper public API is designed.
|
|
|
|
Example running Python code between "Core" and "Main" initialization
|
|
phases::
|
|
|
|
void init_python(void)
|
|
{
|
|
PyStatus status;
|
|
|
|
PyConfig config;
|
|
PyConfig_InitPythonConfig(&config);
|
|
config._init_main = 0;
|
|
|
|
/* ... customize 'config' configuration ... */
|
|
|
|
status = Py_InitializeFromConfig(&config);
|
|
PyConfig_Clear(&config);
|
|
if (PyStatus_Exception(status)) {
|
|
Py_ExitStatusException(status);
|
|
}
|
|
|
|
/* Use sys.stderr because sys.stdout is only created
|
|
by _Py_InitializeMain() */
|
|
int res = PyRun_SimpleString(
|
|
"import sys; "
|
|
"print('Run Python code before _Py_InitializeMain', "
|
|
"file=sys.stderr)");
|
|
if (res < 0) {
|
|
exit(1);
|
|
}
|
|
|
|
/* ... put more configuration code here ... */
|
|
|
|
status = _Py_InitializeMain();
|
|
if (PyStatus_Exception(status)) {
|
|
Py_ExitStatusException(status);
|
|
}
|
|
}
|