Python 初始化設定¶

PyInitConfig C API¶

在 3.14 版被加入.

Python 可以使用 Py_InitializeFromInitConfig() 來初始化。

The Py_RunMain() function can be used to write a customized Python program.

也參考

PEP 741 "Python Configuration C API".

範例¶

Example of customized Python always running with the Python Development Mode enabled; return -1 on error:

int init_python(void)
{
    PyInitConfig *config = PyInitConfig_Create();
    if (config == NULL) {
        printf("PYTHON INIT ERROR: memory allocation failed\n");
        return -1;
    }

    // Enable the Python Development Mode
    if (PyInitConfig_SetInt(config, "dev_mode", 1) < 0) {
        goto error;
    }

    // Initialize Python with the configuration
    if (Py_InitializeFromInitConfig(config) < 0) {
        goto error;
    }
    PyInitConfig_Free(config);
    return 0;

error:
    {
        // Display the error message.
        //
        // This uncommon braces style is used, because you cannot make
        // goto targets point to variable declarations.
        const char *err_msg;
        (void)PyInitConfig_GetError(config, &err_msg);
        printf("PYTHON INIT ERROR: %s\n", err_msg);
        PyInitConfig_Free(config);
        return -1;
    }
}

建立設定¶

struct PyInitConfig¶: Opaque structure to configure the Python initialization.

PyInitConfig *PyInitConfig_Create(void)¶

Create a new initialization configuration using Isolated Configuration default values.

必須由 PyInitConfig_Free() 來釋放。

在記憶體配置失敗時回傳 NULL。

void PyInitConfig_Free(PyInitConfig *config)¶

釋放初始化配置 config 的記憶體。

如果 config 是 NULL，則不執行任何操作。

錯誤處理¶

int PyInitConfig_GetError(PyInitConfig *config, const char **err_msg)¶

取得 config 錯誤訊息。

如果設定了錯誤，則設置 *err_msg 並回傳 1。
如果沒有設定錯誤，則設定 *err_msg 為 NULL 並回傳 0。

錯誤訊息是 UTF-8 編碼的字串。

If config has an exit code, format the exit code as an error message.

The error message remains valid until another PyInitConfig function is called with config. The caller doesn't have to free the error message.

int PyInitConfig_GetExitCode(PyInitConfig *config, int *exitcode)¶

Get the config exit code.

Set *exitcode and return 1 if config has an exit code set.
Return 0 if config has no exit code set.

Only the Py_InitializeFromInitConfig() function can set an exit code if the parse_argv option is non-zero.

An exit code can be set when parsing the command line failed (exit code 2) or when a command line option asks to display the command line help (exit code 0).

Get Options¶

The configuration option name parameter must be a non-NULL null-terminated UTF-8 encoded string. See Configuration Options.

int PyInitConfig_HasOption(PyInitConfig *config, const char *name)¶

測試配置是否有名為 name 的選項。

如果選項存在則回傳 1，否則回傳 0。

int PyInitConfig_GetInt(PyInitConfig *config, const char *name, int64_t *value)¶

Get an integer configuration option.

Set *value, and return 0 on success.
Set an error in config and return -1 on error.

int PyInitConfig_GetStr(PyInitConfig *config, const char *name, char **value)¶

Get a string configuration option as a null-terminated UTF-8 encoded string.

Set *value, and return 0 on success.
Set an error in config and return -1 on error.

*value can be set to NULL if the option is an optional string and the option is unset.

On success, the string must be released with free(value) if it's not NULL.

int PyInitConfig_GetStrList(PyInitConfig *config, const char *name, size_t *length, char ***items)¶

Get a string list configuration option as an array of null-terminated UTF-8 encoded strings.

Set *length and *value, and return 0 on success.
Set an error in config and return -1 on error.

On success, the string list must be released with PyInitConfig_FreeStrList(length, items).

void PyInitConfig_FreeStrList(size_t length, char **items)¶: Free memory of a string list created by PyInitConfig_GetStrList().

Set Options¶

The configuration option name parameter must be a non-NULL null-terminated UTF-8 encoded string. See Configuration Options.

Some configuration options have side effects on other options. This logic is only implemented when Py_InitializeFromInitConfig() is called, not by the "Set" functions below. For example, setting dev_mode to 1 does not set faulthandler to 1.

int PyInitConfig_SetInt(PyInitConfig *config, const char *name, int64_t value)¶

Set an integer configuration option.

成功時回傳 0。
Set an error in config and return -1 on error.

int PyInitConfig_SetStr(PyInitConfig *config, const char *name, const char *value)¶

Set a string configuration option from a null-terminated UTF-8 encoded string. The string is copied.

成功時回傳 0。
Set an error in config and return -1 on error.

int PyInitConfig_SetStrList(PyInitConfig *config, const char *name, size_t length, char *const *items)¶

Set a string list configuration option from an array of null-terminated UTF-8 encoded strings. The string list is copied.

成功時回傳 0。
Set an error in config and return -1 on error.

模組¶

int PyInitConfig_AddModule(PyInitConfig *config, const char *name, PyObject *(*initfunc)(void))¶

Add a built-in extension module to the table of built-in modules.

The new module can be imported by the name name, and uses the function initfunc as the initialization function called on the first attempted import.

成功時回傳 0。
Set an error in config and return -1 on error.

If Python is initialized multiple times, PyInitConfig_AddModule() must be called at each Python initialization.

和 PyImport_AppendInittab() 函式類似。

初始化 Python¶

int Py_InitializeFromInitConfig(PyInitConfig *config)¶

Initialize Python from the initialization configuration.

成功時回傳 0。
Set an error in config and return -1 on error.
Set an exit code in config and return -1 if Python wants to exit.

See PyInitConfig_GetExitcode() for the exit code case.

Configuration Options¶

選項	PyConfig/PyPreConfig 成員	Type	Visibility
`"allocator"`	`allocator`	`int`	唯讀
`"argv"`	`argv`	`list[str]`	公開
`"base_exec_prefix"`	`base_exec_prefix`	`str`	公開
`"base_executable"`	`base_executable`	`str`	公開
`"base_prefix"`	`base_prefix`	`str`	公開
`"buffered_stdio"`	`buffered_stdio`	`bool`	唯讀
`"bytes_warning"`	`bytes_warning`	`int`	公開
`"check_hash_pycs_mode"`	`check_hash_pycs_mode`	`str`	唯讀
`"code_debug_ranges"`	`code_debug_ranges`	`bool`	唯讀
`"coerce_c_locale"`	`coerce_c_locale`	`bool`	唯讀
`"coerce_c_locale_warn"`	`coerce_c_locale_warn`	`bool`	唯讀
`"configure_c_stdio"`	`configure_c_stdio`	`bool`	唯讀
`"configure_locale"`	`configure_locale`	`bool`	唯讀
`"cpu_count"`	`cpu_count`	`int`	公開
`"dev_mode"`	`dev_mode`	`bool`	唯讀
`"dump_refs"`	`dump_refs`	`bool`	唯讀
`"dump_refs_file"`	`dump_refs_file`	`str`	唯讀
`"exec_prefix"`	`exec_prefix`	`str`	公開
`"executable"`	`executable`	`str`	公開
`"faulthandler"`	`faulthandler`	`bool`	唯讀
`"filesystem_encoding"`	`filesystem_encoding`	`str`	唯讀
`"filesystem_errors"`	`filesystem_errors`	`str`	唯讀
`"hash_seed"`	`hash_seed`	`int`	唯讀
`"home"`	`home`	`str`	唯讀
`"import_time"`	`import_time`	`int`	唯讀
`"inspect"`	`inspect`	`bool`	公開
`"install_signal_handlers"`	`install_signal_handlers`	`bool`	唯讀
`"int_max_str_digits"`	`int_max_str_digits`	`int`	公開
`"interactive"`	`interactive`	`bool`	公開
`"isolated"`	`isolated`	`bool`	唯讀
`"legacy_windows_fs_encoding"`	`legacy_windows_fs_encoding`	`bool`	唯讀
`"legacy_windows_stdio"`	`legacy_windows_stdio`	`bool`	唯讀
`"malloc_stats"`	`malloc_stats`	`bool`	唯讀
`"module_search_paths"`	`module_search_paths`	`list[str]`	公開
`"optimization_level"`	`optimization_level`	`int`	公開
`"orig_argv"`	`orig_argv`	`list[str]`	唯讀
`"parse_argv"`	`parse_argv`	`bool`	唯讀
`"parser_debug"`	`parser_debug`	`bool`	公開
`"pathconfig_warnings"`	`pathconfig_warnings`	`bool`	唯讀
`"perf_profiling"`	`perf_profiling`	`bool`	唯讀
`"platlibdir"`	`platlibdir`	`str`	公開
`"prefix"`	`prefix`	`str`	公開
`"surrogateescape"`	`program_name`	`str`	唯讀
`"pycache_prefix"`	`pycache_prefix`	`str`	公開
`"quiet"`	`quiet`	`bool`	公開
`"run_command"`	`run_command`	`str`	唯讀
`"run_filename"`	`run_filename`	`str`	唯讀
`"run_module"`	`run_module`	`str`	唯讀
`"run_presite"`	`run_presite`	`str`	唯讀
`"safe_path"`	`safe_path`	`bool`	唯讀
`"show_ref_count"`	`show_ref_count`	`bool`	唯讀
`"site_import"`	`site_import`	`bool`	唯讀
`"skip_source_first_line"`	`skip_source_first_line`	`bool`	唯讀
`"stdio_encoding"`	`stdio_encoding`	`str`	唯讀
`"stdio_errors"`	`stdio_errors`	`str`	唯讀
`"stdlib_dir"`	`stdlib_dir`	`str`	公開
`"tracemalloc"`	`tracemalloc`	`int`	唯讀
`"use_environment"`	`use_environment`	`bool`	公開
`"use_frozen_modules"`	`use_frozen_modules`	`bool`	唯讀
`"use_hash_seed"`	`use_hash_seed`	`bool`	唯讀
`"use_system_logger"`	`use_system_logger`	`bool`	唯讀
`"user_site_directory"`	`user_site_directory`	`bool`	唯讀
`"utf8_mode"`	`utf8_mode`	`bool`	唯讀
`"verbose"`	`verbose`	`int`	公開
`"warn_default_encoding"`	`warn_default_encoding`	`bool`	唯讀
`"warnoptions"`	`warnoptions`	`list[str]`	公開
`"write_bytecode"`	`write_bytecode`	`bool`	公開
`"xoptions"`	`xoptions`	`dict[str, str]`	公開
`"_pystats"`	`_pystats`	`bool`	唯讀

Visibility:

Public: Can be retrieved by PyConfig_Get() and set by PyConfig_Set().
Read-only: Can be retrieved by PyConfig_Get(), but cannot be set by PyConfig_Set().

Runtime Python configuration API¶

At runtime, it's possible to get and set configuration options using PyConfig_Get() and PyConfig_Set() functions.

The configuration option name parameter must be a non-NULL null-terminated UTF-8 encoded string. See Configuration Options.

Some options are read from the sys attributes. For example, the option "argv" is read from sys.argv.

PyObject *PyConfig_Get(const char *name)¶

Get the current runtime value of a configuration option as a Python object.

Return a new reference on success.
Set an exception and return NULL on error.

The object type depends on the configuration option. It can be:

bool
int
str
list[str]
dict[str, str]

The caller must have an attached thread state. The function cannot be called before Python initialization nor after Python finalization.

在 3.14 版被加入.

int PyConfig_GetInt(const char *name, int *value)¶

Similar to PyConfig_Get(), but get the value as a C int.

成功時回傳 0。
Set an exception and return -1 on error.

在 3.14 版被加入.

PyObject *PyConfig_Names(void)¶

Get all configuration option names as a frozenset.

Return a new reference on success.
Set an exception and return NULL on error.

The caller must have an attached thread state. The function cannot be called before Python initialization nor after Python finalization.

在 3.14 版被加入.

int PyConfig_Set(const char *name, PyObject *value)¶

Set the current runtime value of a configuration option.

如果沒有選項 name，則引發 ValueError。
如果 value 是無效值，則引發 ValueError。
如果選項是唯讀的（無法設定），則引發 ValueError。
Raise a TypeError if value has not the proper type.

The caller must have an attached thread state. The function cannot be called before Python initialization nor after Python finalization.

Raises an auditing event cpython.PyConfig_Set with arguments name, value.

在 3.14 版被加入.

PyConfig C API¶

在 3.8 版被加入.

Python can be initialized with Py_InitializeFromConfig() and the PyConfig structure. It can be preinitialized with Py_PreInitialize() and the PyPreConfig structure.

There are two kinds of configuration:

The Python Configuration can be used to build a customized Python which behaves as the regular Python. For example, environment variables and command line arguments are used to configure Python.
The Isolated Configuration can be used to embed Python into an application. It isolates Python from the system. For example, environment variables are ignored, the LC_CTYPE locale is left unchanged and no signal handler is registered.

The Py_RunMain() function can be used to write a customized Python program.

也參考

PEP 587 "Python Initialization Configuration".

範例¶

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 exception;
    }

    status = Py_InitializeFromConfig(&config);
    if (PyStatus_Exception(status)) {
        goto exception;
    }
    PyConfig_Clear(&config);

    return Py_RunMain();

exception:
    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);
}

PyWideStringList¶

type PyWideStringList¶

wchar_t* 字串串列。

If length is non-zero, items must be non-NULL and all strings must be non-NULL.

方法：

PyStatus PyWideStringList_Append(PyWideStringList *list, const wchar_t *item)¶

Append item to list.

Python must be preinitialized to call this function.

PyStatus PyWideStringList_Insert(PyWideStringList *list, Py_ssize_t index, const wchar_t *item)¶

Insert item into list at index.

If index is greater than or equal to list length, append item to list.

index must be greater than or equal to 0.

Python must be preinitialized to call this function.

Structure fields:

Py_ssize_t length¶: 串列長度。

wchar_t **items¶: List items.

PyStatus¶

type PyStatus¶

Structure to store an initialization function status: success, error or exit.

For an error, it can store the C function name which created the error.

Structure fields:

int exitcode¶: Exit code. Argument passed to exit().

const char *err_msg¶: 錯誤訊息。

const char *func¶: Name of the function which created an error, can be NULL.

建立狀態的函式：

PyStatus PyStatus_Ok(void)¶: 成功。

PyStatus PyStatus_Error(const char *err_msg)¶

附帶訊息的初始化錯誤。

err_msg 不可為 NULL。

PyStatus PyStatus_NoMemory(void)¶: Memory allocation failure (out of memory).

PyStatus PyStatus_Exit(int exitcode)¶: 以指定的退出代號退出 Python。

處理狀態的函式：

int PyStatus_Exception(PyStatus status)¶: Is the status an error or an exit? If true, the exception must be handled; by calling Py_ExitStatusException() for example.

int PyStatus_IsError(PyStatus status)¶: Is the result an error?

int PyStatus_IsExit(PyStatus status)¶: Is the result an exit?

void Py_ExitStatusException(PyStatus status)¶: Call exit(exitcode) if status is an exit. Print the error message and exit with a non-zero exit code if status is an error. Must only be called if PyStatus_Exception(status) is non-zero.

備註

Internally, Python uses macros which set PyStatus.func, whereas functions to create a status set func to NULL.

範例：

PyStatus alloc(void **ptr, size_t size)
{
    *ptr = PyMem_RawMalloc(size);
    if (*ptr == NULL) {
        return PyStatus_NoMemory();
    }
    return PyStatus_Ok();
}

int main(int argc, char **argv)
{
    void *ptr;
    PyStatus status = alloc(&ptr, 16);
    if (PyStatus_Exception(status)) {
        Py_ExitStatusException(status);
    }
    PyMem_Free(ptr);
    return 0;
}

PyPreConfig¶

type PyPreConfig¶

Structure used to preinitialize Python.

Function to initialize a preconfiguration:

void PyPreConfig_InitPythonConfig(PyPreConfig *preconfig)¶: Initialize the preconfiguration with Python Configuration.

void PyPreConfig_InitIsolatedConfig(PyPreConfig *preconfig)¶: Initialize the preconfiguration with Isolated Configuration.

Structure fields:

int allocator¶

Name of the Python memory allocators:

PYMEM_ALLOCATOR_NOT_SET (0): don't change memory allocators (use defaults).
PYMEM_ALLOCATOR_DEFAULT (1): default memory allocators.
PYMEM_ALLOCATOR_DEBUG (2): default memory allocators with debug hooks.
PYMEM_ALLOCATOR_MALLOC (3): use malloc() of the C library.
PYMEM_ALLOCATOR_MALLOC_DEBUG (4): force usage of malloc() with debug hooks.
PYMEM_ALLOCATOR_PYMALLOC (5): Python pymalloc memory allocator.
PYMEM_ALLOCATOR_PYMALLOC_DEBUG (6): Python pymalloc memory allocator with debug hooks.
PYMEM_ALLOCATOR_MIMALLOC (6): use mimalloc, a fast malloc replacement.
PYMEM_ALLOCATOR_MIMALLOC_DEBUG (7): use mimalloc, a fast malloc replacement with debug hooks.

PYMEM_ALLOCATOR_PYMALLOC and PYMEM_ALLOCATOR_PYMALLOC_DEBUG are not supported if Python is configured using --without-pymalloc.

PYMEM_ALLOCATOR_MIMALLOC and PYMEM_ALLOCATOR_MIMALLOC_DEBUG are not supported if Python is configured using --without-mimalloc or if the underlying atomic support isn't available.

請見記憶體管理。

預設：PYMEM_ALLOCATOR_NOT_SET。

int configure_locale¶

Set the LC_CTYPE locale to the user preferred locale.

If equals to 0, set coerce_c_locale and coerce_c_locale_warn members to 0.

請見 locale encoding。

Default: 1 in Python config, 0 in isolated config.

int coerce_c_locale¶

If equals to 2, coerce the C locale.

If equals to 1, read the LC_CTYPE locale to decide if it should be coerced.

請見 locale encoding。

Default: -1 in Python config, 0 in isolated config.

int coerce_c_locale_warn¶

If non-zero, emit a warning if the C locale is coerced.

Default: -1 in Python config, 0 in isolated config.

int dev_mode¶

Python Development Mode: see PyConfig.dev_mode.

Default: -1 in Python mode, 0 in isolated mode.

int isolated¶

Isolated mode: see PyConfig.isolated.

Default: 0 in Python mode, 1 in isolated mode.

int legacy_windows_fs_encoding¶

如果不為 0：

將 PyPreConfig.utf8_mode 設為 0、
將 PyConfig.filesystem_encoding 設為 "mbcs"、
將 PyConfig.filesystem_errors 設為 "replace"。

Initialized from the PYTHONLEGACYWINDOWSFSENCODING environment variable value.

Only available on Windows. #ifdef MS_WINDOWS macro can be used for Windows specific code.

預設：0。

int parse_argv¶

If non-zero, Py_PreInitializeFromArgs() and Py_PreInitializeFromBytesArgs() parse their argv argument the same way the regular Python parses command line arguments: see Command Line Arguments.

Default: 1 in Python config, 0 in isolated config.

int use_environment¶

Use environment variables? See PyConfig.use_environment.

Default: 1 in Python config and 0 in isolated config.

int utf8_mode¶

If non-zero, enable the Python UTF-8 Mode.

Set to 0 or 1 by the -X utf8 command line option and the PYTHONUTF8 environment variable.

Also set to 1 if the LC_CTYPE locale is C or POSIX.

Default: -1 in Python config and 0 in isolated config.

Preinitialize Python with PyPreConfig¶

The preinitialization of Python:

Set the Python memory allocators (PyPreConfig.allocator)
Configure the LC_CTYPE locale (locale encoding)
Set the Python UTF-8 Mode (PyPreConfig.utf8_mode)

The current preconfiguration (PyPreConfig type) is stored in _PyRuntime.preconfig.

Functions to preinitialize Python:

PyStatus Py_PreInitialize(const PyPreConfig *preconfig)¶

Preinitialize Python from preconfig preconfiguration.

preconfig 不可為 NULL。

PyStatus Py_PreInitializeFromBytesArgs(const PyPreConfig *preconfig, int argc, char *const *argv)¶

Preinitialize Python from preconfig preconfiguration.

Parse argv command line arguments (bytes strings) if parse_argv of preconfig is non-zero.

preconfig 不可為 NULL。

PyStatus Py_PreInitializeFromArgs(const PyPreConfig *preconfig, int argc, wchar_t *const *argv)¶

Preinitialize Python from preconfig preconfiguration.

Parse argv command line arguments (wide strings) if parse_argv of preconfig is non-zero.

preconfig 不可為 NULL。

The caller is responsible to handle exceptions (error or exit) using PyStatus_Exception() and Py_ExitStatusException().

For Python Configuration (PyPreConfig_InitPythonConfig()), if Python is initialized with command line arguments, the command line arguments must also be passed to preinitialize Python, since they have an effect on the pre-configuration like encodings. For example, the -X utf8 command line option enables the Python UTF-8 Mode.

PyMem_SetAllocator() can be called after Py_PreInitialize() and before Py_InitializeFromConfig() to install a custom memory allocator. It can be called before Py_PreInitialize() if PyPreConfig.allocator is set to PYMEM_ALLOCATOR_NOT_SET.

Python memory allocation functions like PyMem_RawMalloc() must not be used before the Python preinitialization, whereas calling directly malloc() and free() is always safe. Py_DecodeLocale() must not be called before the Python preinitialization.

Example using the preinitialization to enable the Python UTF-8 Mode:

PyStatus status;
PyPreConfig preconfig;
PyPreConfig_InitPythonConfig(&preconfig);

preconfig.utf8_mode = 1;

status = Py_PreInitialize(&preconfig);
if (PyStatus_Exception(status)) {
    Py_ExitStatusException(status);
}

/* at this point, Python speaks UTF-8 */

Py_Initialize();
/* ... use Python API here ... */
Py_Finalize();

PyConfig¶

type PyConfig¶

Structure containing most parameters to configure Python.

When done, the PyConfig_Clear() function must be used to release the configuration memory.

Structure methods:

void PyConfig_InitPythonConfig(PyConfig *config)¶: Initialize configuration with the Python Configuration.

void PyConfig_InitIsolatedConfig(PyConfig *config)¶: Initialize configuration with the Isolated Configuration.

PyStatus PyConfig_SetString(PyConfig *config, wchar_t *const *config_str, const wchar_t *str)¶

Copy the wide character string str into *config_str.

Preinitialize Python if needed.

PyStatus PyConfig_SetBytesString(PyConfig *config, wchar_t *const *config_str, const char *str)¶

Decode str using Py_DecodeLocale() and set the result into *config_str.

Preinitialize Python if needed.

PyStatus PyConfig_SetArgv(PyConfig *config, int argc, wchar_t *const *argv)¶

Set command line arguments (argv member of config) from the argv list of wide character strings.

Preinitialize Python if needed.

PyStatus PyConfig_SetBytesArgv(PyConfig *config, int argc, char *const *argv)¶

Set command line arguments (argv member of config) from the argv list of bytes strings. Decode bytes using Py_DecodeLocale().

Preinitialize Python if needed.

PyStatus PyConfig_SetWideStringList(PyConfig *config, PyWideStringList *list, Py_ssize_t length, wchar_t **items)¶: Set the list of wide strings