Python初始化配置¶
3.8 新版功能.
结构
函数
The preconfiguration (PyPreConfig
type) is stored in
_PyRuntime.preconfig
and the configuration (PyConfig
type) is stored in
PyInterpreterState.config
.
参见 Initialization, Finalization, and Threads.
参见
PEP 587 "Python 初始化配置".
PyWideStringList¶
-
PyWideStringList
¶ 由
wchar_t*
字符串组成的列表。如果 length 为非零值,则 items 必须不为
NULL
并且所有字符串均必须不为NULL
。方法
-
PyStatus
PyWideStringList_Append
(PyWideStringList *list, const wchar_t *item)¶ 将 item 添加到 list。
Python 必须被预初始化以便调用此函数。
-
PyStatus
PyWideStringList_Insert
(PyWideStringList *list, Py_ssize_t index, const wchar_t *item)¶ 将 item 插入到 list 的 index 位置上。
如果 index 大于等于 list 的长度,则将 item 添加到 list。
index must be greater than or equal to 0.
Python 必须被预初始化以便调用此函数。
结构体字段:
-
Py_ssize_t
length
¶ List 长度。
-
wchar_t**
items
¶ 列表项目。
-
PyStatus
PyStatus¶
-
PyStatus
¶ 存储初始函数状态:成功、错误或退出的结构体。
对于错误,它可以存储造成错误的 C 函数的名称。
结构体字段:
-
int
exitcode
¶ 退出码。 传给
exit()
的参数。
-
const char *
err_msg
¶ 错误信息
-
const char *
func
¶ 造成错误的函数的名称,可以为
NULL
。
创建状态的函数:
处理状态的函数:
-
int
PyStatus_Exception
(PyStatus status)¶ 状态为错误还是退出?如为真值,则异常必须被处理;例如通过调用
Py_ExitStatusException()
。
-
int
注解
在内部,Python 将使用设置 PyStatus.func
的宏,而创建状态的函数则会将 func
设为 NULL
。
示例:
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¶
-
PyPreConfig
¶ Structure used to preinitialize Python:
Set the Python memory allocator
Configure the LC_CTYPE locale
设置为 UTF-8 模式
用于初始化预先配置的函数:
-
void
PyPreConfig_InitPythonConfig
(PyPreConfig *preconfig)¶ 通过 Python 配置 来初始化预先配置。
-
void
PyPreConfig_InitIsolatedConfig
(PyPreConfig *preconfig)¶ 通过 隔离配置 来初始化预先配置。
结构体字段:
-
int
allocator
¶ Name of the memory allocator:
PYMEM_ALLOCATOR_NOT_SET
(0
): don't change memory allocators (use defaults)PYMEM_ALLOCATOR_DEFAULT
(1
): default memory allocatorsPYMEM_ALLOCATOR_DEBUG
(2
): default memory allocators with debug hooksPYMEM_ALLOCATOR_MALLOC
(3
): force usage ofmalloc()
PYMEM_ALLOCATOR_MALLOC_DEBUG
(4
): force usage ofmalloc()
with debug hooksPYMEM_ALLOCATOR_PYMALLOC
(5
): Python pymalloc memory allocatorPYMEM_ALLOCATOR_PYMALLOC_DEBUG
(6
): Python pymalloc memory allocator with debug hooks
PYMEM_ALLOCATOR_PYMALLOC
andPYMEM_ALLOCATOR_PYMALLOC_DEBUG
are not supported if Python is configured using--without-pymalloc
-
int
configure_locale
¶ Set the LC_CTYPE locale to the user preferred locale? If equals to 0, set
coerce_c_locale
andcoerce_c_locale_warn
to 0.
-
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.
-
int
coerce_c_locale_warn
¶ 如为非零值,则会在 C 语言区域被强制转换时发出警告。
-
int
dev_mode
¶
-
int
isolated
¶
-
int
legacy_windows_fs_encoding
(Windows only)¶ If non-zero, disable UTF-8 Mode, set the Python filesystem encoding to
mbcs
, set the filesystem error handler toreplace
.仅在 Windows 上可用。
#ifdef MS_WINDOWS
宏可被用于 Windows 专属的代码。
-
int
parse_argv
¶ 如为非零值,
Py_PreInitializeFromArgs()
和Py_PreInitializeFromBytesArgs()
将以与常规 Python 解析命令行参数的相同方式解析其argv
参数:参见 命令行参数。
-
int
use_environment
¶
-
int
utf8_mode
¶ If non-zero, enable the UTF-8 mode.
Preinitialization with PyPreConfig¶
用于预初始化 Python 的函数:
-
PyStatus
Py_PreInitialize
(const PyPreConfig *preconfig)¶ 根据 preconfig 预配置来预初始化 Python。
-
PyStatus
Py_PreInitializeFromBytesArgs
(const PyPreConfig *preconfig, int argc, char * const *argv)¶ Preinitialize Python from preconfig preconfiguration and command line arguments (bytes strings).
-
PyStatus
Py_PreInitializeFromArgs
(const PyPreConfig *preconfig, int argc, wchar_t * const * argv)¶ Preinitialize Python from preconfig preconfiguration and command line arguments (wide strings).
调用方要负责使用 PyStatus_Exception()
和 Py_ExitStatusException()
来处理异常(错误或退出)。
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 UTF-8 Mode.
PyMem_SetAllocator()
可在 Py_PreInitialize()
之后、Py_InitializeFromConfig()
之前被调用以安装自定义的内存分配器。 如果 PyPreConfig.allocator
被设为 PYMEM_ALLOCATOR_NOT_SET
则可在 Py_PreInitialize()
之前被调用。
Python memory allocation functions like PyMem_RawMalloc()
must not be
used before Python preinitialization, whereas calling directly malloc()
and
free()
is always safe. Py_DecodeLocale()
must not be called before
the preinitialization.
Example using the preinitialization to enable the 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 will speak UTF-8 */
Py_Initialize();
/* ... use Python API here ... */
Py_Finalize();
PyConfig¶
-
PyConfig
¶ 包含了大部分用于配置 Python 的形参的结构体。
结构体方法:
-
void
PyConfig_InitPythonConfig
(PyConfig *config)¶ Initialize configuration with Python Configuration.
-
void
PyConfig_InitIsolatedConfig
(PyConfig *config)¶ Initialize configuration with Isolated Configuration.
-
PyStatus
PyConfig_SetString
(PyConfig *config, wchar_t * const *config_str, const wchar_t *str)¶ 将宽字符串 str 拷贝至
*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 from wide character strings.
Preinitialize Python if needed.
-
PyStatus
PyConfig_SetBytesArgv
(PyConfig *config, int argc, char * const *argv)¶ Set command line arguments: decode bytes using
Py_DecodeLocale()
.Preinitialize Python if needed.
-
PyStatus
PyConfig_SetWideStringList
(PyConfig *config, PyWideStringList *list, Py_ssize_t length, wchar_t **items)¶ 将宽字符串列表 list 设置为 length 和 items。
Preinitialize Python if needed.
-
PyStatus
PyConfig_Read
(PyConfig *config)¶ 读取所有 Python 配置。
已经初始化的字段会保持不变。
Preinitialize Python if needed.
Most
PyConfig
methods preinitialize Python if needed. In that case, the Python preinitialization configuration in based on thePyConfig
. If configuration fields which are in common withPyPreConfig
are tuned, they must be set before calling aPyConfig
method:Moreover, if
PyConfig_SetArgv()
orPyConfig_SetBytesArgv()
is used, this method must be called first, before other methods, since the preinitialization configuration depends on command line arguments (ifparse_argv
is non-zero).这些方法的调用者要负责使用
PyStatus_Exception()
和Py_ExitStatusException()
来处理异常(错误或退出)。结构体字段:
-
PyWideStringList
argv
¶ Command line arguments,
sys.argv
. Seeparse_argv
to parseargv
the same way the regular Python parses Python command line arguments. Ifargv
is empty, an empty string is added to ensure thatsys.argv
always exists and is never empty.
-
wchar_t*
base_exec_prefix
¶
-
wchar_t*
base_executable
¶ sys._base_executable
:__PYVENV_LAUNCHER__
environment variable value, or copy ofPyConfig.executable
.
-
wchar_t*
base_prefix
¶
-
int
buffered_stdio
¶ If equals to 0, enable unbuffered mode, making the stdout and stderr streams unbuffered.
stdin 始终以缓冲模式打开。
-
int
bytes_warning
¶ If equals to 1, issue a warning when comparing
bytes
orbytearray
withstr
, or comparingbytes
withint
. If equal or greater to 2, raise aBytesWarning
exception.
-
wchar_t*
check_hash_pycs_mode
¶ Control the validation behavior of hash-based
.pyc
files (see PEP 552):--check-hash-based-pycs
command line option value.Valid values:
always
,never
anddefault
.默认值为:
default
.
-
int
configure_c_stdio
¶ If non-zero, configure C standard streams (
stdio
,stdout
,stdout
). For example, set their mode toO_BINARY
on Windows.
-
int
dump_refs
¶ 如果为非零值,则转储所有在退出时仍存活的对象。
Require a debug build of Python (
Py_REF_DEBUG
macro must be defined).
-
wchar_t*
exec_prefix
¶
-
wchar_t*
executable
¶
-
int
faulthandler
¶ 如果为非零值,则在启动时调用
faulthandler.enable()
。
-
wchar_t*
filesystem_encoding
¶ Filesystem encoding,
sys.getfilesystemencoding()
.
-
wchar_t*
filesystem_errors
¶ Filesystem encoding errors,
sys.getfilesystemencodeerrors()
.
-
unsigned long
hash_seed
¶
-
int
use_hash_seed
¶ 随机化的哈希函数种子。
If
use_hash_seed
is zero, a seed is chosen randomly at Pythonstartup, andhash_seed
is ignored.
-
wchar_t*
home
¶ Python 主目录。
Initialized from
PYTHONHOME
environment variable value by default.
-
int
import_time
¶ 如为非零值,则对导入时间执行性能分析。
-
int
inspect
¶ 在执行脚本或命令之后进入交互模式。
-
int
install_signal_handlers
¶ Install signal handlers?
-
int
interactive
¶ 交互模式
-
int
isolated
¶ If greater than 0, enable isolated mode:
sys.path
contains neither the script's directory (computed fromargv[0]
or the current directory) nor the user's site-packages directory.Python REPL 将不导入
readline
也不在交互提示符中启用默认的 readline 配置。Set
use_environment
anduser_site_directory
to 0.
-
int
legacy_windows_stdio
¶ If non-zero, use
io.FileIO
instead ofio.WindowsConsoleIO
forsys.stdin
,sys.stdout
andsys.stderr
.仅在 Windows 上可用。
#ifdef MS_WINDOWS
宏可被用于 Windows 专属的代码。
-
int
malloc_stats
¶ 如为非零值,则在退出时转储 Python pymalloc 内存分配器 的统计数据。
The option is ignored if Python is built using
--without-pymalloc
.
-
wchar_t*
pythonpath_env
¶ Module search paths as a string separated by
DELIM
(os.path.pathsep
).Initialized from
PYTHONPATH
environment variable value by default.
-
PyWideStringList
module_search_paths
¶
-
int
module_search_paths_set
¶ sys.path
. Ifmodule_search_paths_set
is equal to 0, themodule_search_paths
is overridden by the function calculating the Path Configuration.
-
int
optimization_level
¶ 编译优化级别:
0: Peephole optimizer (and
__debug__
is set toTrue
)1: Remove assertions, set
__debug__
toFalse
2: Strip docstrings
-
int
parse_argv
¶ If non-zero, parse
argv
the same way the regular Python command line arguments, and strip Python arguments fromargv
: see Command Line Arguments.
-
int
parser_debug
¶ If non-zero, turn on parser debugging output (for expert only, depending on compilation options).
-
int
pathconfig_warnings
¶ If equal to 0, suppress warnings when calculating the Path Configuration (Unix only, Windows does not log any warning). Otherwise, warnings are written into
stderr
.
-
wchar_t*
prefix
¶
-
wchar_t*
program_name
¶ Program name. Used to initialize
executable
, and in early error messages.
-
wchar_t*
pycache_prefix
¶ sys.pycache_prefix
:.pyc
cache prefix.如果为
NULL
,则sys.pycache_prefix
将被设为None
。
-
int
quiet
¶ Quiet mode. For example, don't display the copyright and version messages in interactive mode.
-
wchar_t*
run_command
¶ python3 -c COMMAND
argument. Used byPy_RunMain()
.
-
wchar_t*
run_filename
¶ python3 FILENAME
argument. Used byPy_RunMain()
.
-
wchar_t*
run_module
¶ python3 -m MODULE
argument. Used byPy_RunMain()
.
-
int
show_alloc_count
¶ Show allocation counts at exit?
Set to 1 by
-X showalloccount
command line option.Need a special Python build with
COUNT_ALLOCS
macro defined.
-
int
show_ref_count
¶ 在退出时显示引用总数?
Set to 1 by
-X showrefcount
command line option.Need a debug build of Python (
Py_REF_DEBUG
macro must be defined).
-
int
skip_source_first_line
¶ Skip the first line of the source?
-
wchar_t*
stdio_encoding
¶
-
wchar_t*
stdio_errors
¶ Encoding and encoding errors of
sys.stdin
,sys.stdout
andsys.stderr
.
-
int
tracemalloc
¶ 如果为非零值,则在启动时调用
tracemalloc.start()
。
-
int
use_environment
¶ If greater than 0, use environment variables.
-
int
verbose
¶ If non-zero, enable verbose mode.
-
PyWideStringList
warnoptions
¶ sys.warnoptions
: options of thewarnings
module to build warnings filters: lowest to highest priority.warnings
模块以相反的顺序添加sys.warnoptions
: 最后一个PyConfig.warnoptions
条目将成为warnings.filters
的第一个条目并将最先被检查(最高优先级)。
-
int
write_bytecode
¶ If non-zero, write
.pyc
files.sys.dont_write_bytecode
会被初始化为write_bytecode
取反后的值。
-
PyWideStringList
xoptions
¶
-
void
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 Command Line Arguments.
The xoptions
options are parsed to set other options: see -X
option.
使用 PyConfig 初始化¶
用于初始化 Python 的函数:
调用方要负责使用 PyStatus_Exception()
和 Py_ExitStatusException()
来处理异常(错误或退出)。
If PyImport_FrozenModules
, PyImport_AppendInittab()
or
PyImport_ExtendInittab()
are used, they must be set or called after Python
preinitialization and before the Python initialization.
设置程序名称的示例:
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;
}
隔离配置¶
PyPreConfig_InitIsolatedConfig()
和 PyConfig_InitIsolatedConfig()
函数会创建一个配置来将 Python 与系统隔离开来。 例如,将 Python 嵌入到某个应用程序。
This configuration ignores global configuration variables, environments
variables, command line arguments (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 Path Configuration ("output fields") to ignore these configuration files and avoid the function computing the default path configuration.
Python 配置¶
PyPreConfig_InitPythonConfig()
和 PyConfig_InitPythonConfig()
函数会创建一个配置来构建一个行为与常规 Python 相同的自定义 Python。
环境变量和命令行参数将被用于配置 Python,而全局配置变量将被忽略。
This function enables C locale coercion (PEP 538) and UTF-8 Mode
(PEP 540) depending on the LC_CTYPE locale, PYTHONUTF8
and
PYTHONCOERCECLOCALE
environment variables.
定制的 Python 的示例总是会以隔离模式运行:
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);
}
路径配置¶
PyConfig
包含多个用于路径配置的字段:
路径配置输入:
当前工作目录:用于获取绝对路径
PATH
环境变量用于获取程序的完整路径 (来自PyConfig.program_name
)__PYVENV_LAUNCHER__
环境变量(仅限 Windows only) 注册表 HKEY_CURRENT_USER 和 HKEY_LOCAL_MACHINE 的 "SoftwarePythonPythonCoreX.YPythonPath" 项下的应用程序目录(其中 X.Y 为 Python 版本)。
路径配置输出字段:
If at least one "output field" is not set, Python calculates the path
configuration to fill unset fields. If
module_search_paths_set
is equal to 0,
module_search_paths
is overridden and
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 pathconfig_warnings
to 0 to suppress warnings when
calculating the path configuration (Unix only, Windows does not log any warning).
如果 base_prefix
或 base_exec_prefix
字段未设置,它们将分别从 prefix
和 exec_prefix
继承其值。
Py_RunMain()
和 Py_Main()
将修改 sys.path
:
如果
run_filename
已设置并且是一个包含__main__.py
脚本的目录,则会将run_filename
添加到sys.path
的开头。如果
isolated
为零:如果设置了
run_module
,则将当前目录添加到sys.path
的开头。 如果无法读取当前目录则不执行任何操作。如果设置了
run_filename
,则将文件名的目录添加到sys.path
的开头。在其他情况下,则将一个空字符串添加到
sys.path
的开头。
如果 site_import
为非零值,则 sys.path
可通过 site
模块修改。 如果 user_site_directory
为非零值且用户的 site-package 目录存在,则 site
模块会将用户的 site-package 目录附加到 sys.path
。
路径配置会使用以下配置文件:
pyvenv.cfg
python._pth
(仅Windows)pybuilddir.txt
(仅Unix)
__PYVENV_LAUNCHER__
环境变量将被用于设置 PyConfig.base_executable
Py_RunMain()¶
-
int
Py_RunMain
(void)¶ 执行在命令行或配置中指定的命令 (
PyConfig.run_command
)、脚本 (PyConfig.run_filename
) 或模块 (PyConfig.run_module
)。在默认情况下如果使用了
-i
选项,则运行 REPL。最后,终结化 Python 并返回一个可传递给
exit()
函数的退出状态。
请参阅 Python 配置 查看一个使用 Py_RunMain()
在隔离模式下始终运行自定义 Python 的示例。
多阶段初始化私有暂定 API¶
This section is a private provisional API introducing multi-phase initialization, the core feature of the PEP 432:
“核心”初始化阶段,“最小化的基本 Python”:
"主要"初始化阶段,Python 被完全初始化:
安装并配置
importlib
;应用 路径配置;
安装信号处理器;
完成
sys
模块初始化 (例如:创建sys.stdout
和sys.path
);启用
faulthandler
和tracemalloc
等可选功能;导入
site
模块;等等.
私有临时API:
PyConfig._init_main
: if set to 0,Py_InitializeFromConfig()
stops at the "Core" initialization phase.
在“核心”阶段不会导入任何模块,也不会配置 importlib
模块: 路径配置 只会在“主要”阶段期间应用。 这可能允许在 Python 中定制 Python 以覆盖或微调 路径配置,也可能会安装自定义的 sys.meta_path
导入器或导入钩子等等。
It may become possible to calculatin the Path Configuration in Python, after the Core phase and before the Main phase, which is one of the PEP 432 motivation.
“核心”阶段并没有完整的定义:在这一阶段什么应该可用什么不应该可用都尚未被指明。 该 API 被标记为私有和暂定的:也就是说该 API 可以随时被修改甚至被移除直到设计出适用的公共 API。
在“核心”和“主要”初始化阶段之间运行 Python 代码的示例:
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);
}
}