3.8 版新增。
Structures:
函数:
The preconfiguration (
PyPreConfig
type) is stored in
_PyRuntime.preconfig
and the configuration (
PyConfig
type) is stored in
PyInterpreterState.config
.
另请参阅 初始化、定稿和线程 .
另请参阅
PEP 587 “Python Initialization Configuration”.
PyWideStringList
¶
List of
wchar_t*
strings.
若
length
is non-zero,
items
must be non-
NULL
and all strings must be non-
NULL
.
Methods:
PyWideStringList_Append
(
PyWideStringList
*list
, const wchar_t
*item
)
¶
追加 item to list .
Python must be preinitialized to call this function.
PyWideStringList_Insert
(
PyWideStringList
*list
, Py_ssize_t
index
, const wchar_t
*item
)
¶
Insert item into list at index .
若 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:
length
¶
List length.
items
¶
List items.
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:
exitcode
¶
Exit code. Argument passed to
exit()
.
err_msg
¶
Error message.
func
¶
Name of the function which created an error, can be
NULL
.
Functions to create a status:
Functions to handle a status:
PyStatus_Exception
(
PyStatus
status
)
¶
Is the status an error or an exit? If true, the exception must be handled; by calling
Py_ExitStatusException()
例如。
注意
Internally, Python uses macros which set
PyStatus.func
, whereas functions to create a status set
func
to
NULL
.
范例:
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
¶
Structure used to preinitialize Python:
Set the Python memory allocator
Configure the LC_CTYPE locale
Set the UTF-8 mode
Function to initialize a preconfiguration:
PyPreConfig_InitPythonConfig
(
PyPreConfig
*preconfig
)
¶
Initialize the preconfiguration with Python 配置 .
PyPreConfig_InitIsolatedConfig
(
PyPreConfig
*preconfig
)
¶
Initialize the preconfiguration with 隔离配置 .
Structure fields:
allocator
¶
Name of the memory allocator:
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
): force usage of
malloc()
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_PYMALLOC
and
PYMEM_ALLOCATOR_PYMALLOC_DEBUG
are not supported if Python is configured using
--without-pymalloc
见 内存管理 .
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
to 0.
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.
coerce_c_locale_warn
¶
If non-zero, emit a warning if the C locale is coerced.
dev_mode
¶
isolated
¶
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 to
replace
.
只可用于 Windows。
#ifdef MS_WINDOWS
macro can be used for Windows specific code.
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
命令行自变量
.
use_environment
¶
utf8_mode
¶
If non-zero, enable the UTF-8 mode.
Functions to preinitialize Python:
Py_PreInitialize
(
const
PyPreConfig
*preconfig
)
¶
Preinitialize Python from preconfig preconfiguration.
Py_PreInitializeFromBytesArgs
(
const
PyPreConfig
*preconfig
, int
argc
, char * const
*argv
)
¶
Preinitialize Python from preconfig preconfiguration and command line arguments (bytes strings).
Py_PreInitializeFromArgs
(
const
PyPreConfig
*preconfig
, int
argc
, wchar_t * const *
argv
)
¶
Preinitialize Python from preconfig preconfiguration and command line arguments (wide strings).
The caller is responsible to handle exceptions (error or exit) using
PyStatus_Exception()
and
Py_ExitStatusException()
.
For
Python 配置
(
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()
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
被设为
PYMEM_ALLOCATOR_NOT_SET
.
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
¶
Structure containing most parameters to configure Python.
Structure methods:
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.
PyConfig_SetBytesString
(
PyConfig
*config
, wchar_t * const
*config_str
, const char
*str
)
¶
解码
str
使用
Py_DecodeLocale()
and set the result into
*config_str
.
Preinitialize Python if needed.
PyConfig_SetArgv
(
PyConfig
*config
, int
argc
, wchar_t * const
*argv
)
¶
Set command line arguments from wide character strings.
Preinitialize Python if needed.
PyConfig_SetBytesArgv
(
PyConfig
*config
, int
argc
, char * const
*argv
)
¶
Set command line arguments: decode bytes using
Py_DecodeLocale()
.
Preinitialize Python if needed.
PyConfig_SetWideStringList
(
PyConfig
*config
,
PyWideStringList
*list
, Py_ssize_t
length
, wchar_t
**items
)
¶
Set the list of wide strings list to length and items .
Preinitialize Python if needed.
PyConfig_Read
(
PyConfig
*config
)
¶
Read all Python configuration.
Fields which are already initialized are left unchanged.
Preinitialize Python if needed.
Most
PyConfig
methods preinitialize Python if needed. In that case, the Python preinitialization configuration in based on the
PyConfig
. If configuration fields which are in common with
PyPreConfig
are tuned, they must be set before calling a
PyConfig
方法:
Moreover, if
PyConfig_SetArgv()
or
PyConfig_SetBytesArgv()
is used, this method must be called first, before other methods, since the preinitialization configuration depends on command line arguments (if
parse_argv
is non-zero).
The caller of these methods is responsible to handle exceptions (error or exit) using
PyStatus_Exception()
and
Py_ExitStatusException()
.
Structure fields:
argv
¶
Command line arguments,
sys.argv
。见
parse_argv
to parse
argv
the same way the regular Python parses Python command line arguments. If
argv
is empty, an empty string is added to ensure that
sys.argv
always exists and is never empty.
base_exec_prefix
¶
base_executable
¶
sys._base_executable
:
__PYVENV_LAUNCHER__
environment variable value, or copy of
PyConfig.executable
.
base_prefix
¶
platlibdir
¶
sys.platlibdir
: platform library directory name, set at configure time by
--with-platlibdir
, overrideable by the
PYTHONPLATLIBDIR
环境变量。
3.9 版新增。
buffered_stdio
¶
If equals to 0, enable unbuffered mode, making the stdout and stderr streams unbuffered.
stdin is always opened in buffered mode.
bytes_warning
¶
If equals to 1, issue a warning when comparing
bytes
or
bytearray
with
str
, or comparing
bytes
with
int
. If equal or greater to 2, raise a
BytesWarning
异常。
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
and
default
.
The default value is:
default
.
configure_c_stdio
¶
If non-zero, configure C standard streams (
stdio
,
stdout
,
stdout
). For example, set their mode to
O_BINARY
在 Windows。
dev_mode
¶
If non-zero, enable the Python 开发模式 .
dump_refs
¶
If non-zero, dump all objects which are still alive at exit.
Py_TRACE_REFS
macro must be defined in build.
exec_prefix
¶
executable
¶
faulthandler
¶
If non-zero, call
faulthandler.enable()
at startup.
filesystem_encoding
¶
Filesystem encoding,
sys.getfilesystemencoding()
.
filesystem_errors
¶
Filesystem encoding errors,
sys.getfilesystemencodeerrors()
.
hash_seed
¶
use_hash_seed
¶
Randomized hash function seed.
若
use_hash_seed
is zero, a seed is chosen randomly at Pythonstartup, and
hash_seed
被忽略。
home
¶
Python home directory.
Initialized from
PYTHONHOME
environment variable value by default.
import_time
¶
If non-zero, profile import time.
inspect
¶
Enter interactive mode after executing a script or a command.
install_signal_handlers
¶
Install signal handlers?
interactive
¶
Interactive mode.
isolated
¶
If greater than 0, enable isolated mode:
sys.path
contains neither the script’s directory (computed from
argv[0]
or the current directory) nor the user’s site-packages directory.
Python REPL doesn’t import
readline
nor enable default readline configuration on interactive prompts.
Set
use_environment
and
user_site_directory
to 0.
legacy_windows_stdio
¶
If non-zero, use
io.FileIO
而不是
io.WindowsConsoleIO
for
sys.stdin
,
sys.stdout
and
sys.stderr
.
只可用于 Windows。
#ifdef MS_WINDOWS
macro can be used for Windows specific code.
malloc_stats
¶
If non-zero, dump statistics on Python pymalloc memory allocator at exit.
The option is ignored if Python is built using
--without-pymalloc
.
pythonpath_env
¶
Module search paths as a string separated by
DELIM
(
os.path.pathsep
).
Initialized from
PYTHONPATH
environment variable value by default.
module_search_paths
¶
module_search_paths_set
¶
sys.path
。若
module_search_paths_set
is equal to 0, the
module_search_paths
is overridden by the function calculating the
路径配置
.
optimization_level
¶
Compilation optimization level:
0: Peephole optimizer (and
__debug__
被设为
True
)
1: Remove assertions, set
__debug__
to
False
2: Strip docstrings
parse_argv
¶
If non-zero, parse
argv
the same way the regular Python command line arguments, and strip Python arguments from
argv
: see
命令行自变量
.
parser_debug
¶
If non-zero, turn on parser debugging output (for expert only, depending on compilation options).
pathconfig_warnings
¶
If equal to 0, suppress warnings when calculating the
路径配置
(Unix only, Windows does not log any warning). Otherwise, warnings are written into
stderr
.
prefix
¶
program_name
¶
Program name. Used to initialize
executable
, and in early error messages.
pycache_prefix
¶
sys.pycache_prefix
:
.pyc
cache prefix.
若
NULL
,
sys.pycache_prefix
被设为
None
.
quiet
¶
Quiet mode. For example, don’t display the copyright and version messages in interactive mode.
run_command
¶
python3 -c COMMAND
argument. Used by
Py_RunMain()
.
run_filename
¶
python3 FILENAME
argument. Used by
Py_RunMain()
.
run_module
¶
python3 -m MODULE
argument. Used by
Py_RunMain()
.
show_ref_count
¶
Show total reference count at exit?
Set to 1 by
-X showrefcount
命令行选项。
Need a debug build of Python (
Py_REF_DEBUG
macro must be defined).
skip_source_first_line
¶
Skip the first line of the source?
stdio_encoding
¶
stdio_errors
¶
Encoding and encoding errors of
sys.stdin
,
sys.stdout
and
sys.stderr
.
tracemalloc
¶
If non-zero, call
tracemalloc.start()
at startup.
use_environment
¶
If greater than 0, use environment variables .
verbose
¶
If non-zero, enable verbose mode.
warnoptions
¶
sys.warnoptions
: options of the
warnings
module to build warnings filters: lowest to highest priority.
warnings
module adds
sys.warnoptions
in the reverse order: the last
PyConfig.warnoptions
item becomes the first item of
warnings.filters
which is checked first (highest priority).
write_bytecode
¶
If non-zero, write
.pyc
文件。
sys.dont_write_bytecode
is initialized to the inverted value of
write_bytecode
.
xoptions
¶
_use_peg_parser
¶
Enable PEG parser? Default: 1.
Set to 0 by
-X oldparser
and
PYTHONOLDPARSER
.
另请参阅 PEP 617 .
从 3.9 版起弃用,将在 3.10 版中移除。
若
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
命令行自变量
.
xoptions
options are parsed to set other options: see
-X
选项。
3.9 版改变:
show_alloc_count
field has been removed.
Function to initialize Python:
Py_InitializeFromConfig
(
const
PyConfig
*config
)
¶
Initialize Python from config configuration.
The caller is responsible to handle exceptions (error or exit) using
PyStatus_Exception()
and
Py_ExitStatusException()
.
若
PyImport_FrozenModules()
,
PyImport_AppendInittab()
or
PyImport_ExtendInittab()
are used, they must be set or called after Python preinitialization and before the Python initialization. If Python is initialized multiple times,
PyImport_AppendInittab()
or
PyImport_ExtendInittab()
must be called before each 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;
}
PyPreConfig_InitIsolatedConfig()
and
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 (
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 路径配置 (“output fields”) to ignore these configuration files and avoid the function computing the default path configuration.
PyPreConfig_InitPythonConfig()
and
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,
PYTHONUTF8
and
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);
}
PyConfig
contains multiple fields for the path configuration:
Path configuration inputs:
current working directory: to get absolute paths
PATH
environment variable to get the program full path (from
PyConfig.program_name
)
__PYVENV_LAUNCHER__
环境变量
(Windows only) Application paths in the registry under “SoftwarePythonPythonCoreX.YPythonPath” of HKEY_CURRENT_USER and HKEY_LOCAL_MACHINE (where X.Y is the Python version).
Path configuration output fields:
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
被设为 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).
若
base_prefix
or
base_exec_prefix
fields are not set, they inherit their value from
prefix
and
exec_prefix
分别。
Py_RunMain()
and
Py_Main()
modify
sys.path
:
若
run_filename
is set and is a directory which contains a
__main__.py
script, prepend
run_filename
to
sys.path
.
若
isolated
is zero:
若
run_module
is set, prepend the current directory to
sys.path
. Do nothing if the current directory cannot be read.
若
run_filename
is set, prepend the directory of the filename to
sys.path
.
Otherwise, prepend an empty string to
sys.path
.
若
site_import
is non-zero,
sys.path
can be modified by the
site
module. If
user_site_directory
is non-zero and the user’s site-package directory exists, the
site
module appends the user’s site-package directory to
sys.path
.
The following configuration files are used by the path configuration:
pyvenv.cfg
python._pth
(Windows only)
pybuilddir.txt
(Unix only)
__PYVENV_LAUNCHER__
environment variable is used to set
PyConfig.base_executable
Py_RunMain
(
void
)
¶
Execute the command (
PyConfig.run_command
), the script (
PyConfig.run_filename
) or the module (
PyConfig.run_module
) specified on the command line or in the configuration.
By default and when if
-i
option is used, run the REPL.
Finally, finalizes Python and returns an exit status that can be passed to the
exit()
函数。
见
Python 配置
for an example of customized Python always running in isolated mode using
Py_RunMain()
.
Py_GetArgcArgv
(
int
*argc
, wchar_t
***argv
)
¶
Get the original command line arguments, before Python modified them.
This section is a private provisional API introducing multi-phase initialization, the core feature of the PEP 432 :
“Core” initialization phase, “bare minimum Python”:
“Main” initialization phase, Python is fully initialized:
Install and configure
importlib
;
Apply the 路径配置 ;
Install signal handlers;
Finish
sys
module initialization (ex: create
sys.stdout
and
sys.path
);
Enable optional features like
faulthandler
and
tracemalloc
;
Import the
site
模块;
etc.
Private provisional API:
PyConfig._init_main
: if set to 0,
Py_InitializeFromConfig()
stops at the “Core” initialization phase.
PyConfig._isolated_interpreter
: if non-zero, disallow threads, subprocesses and fork.
_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
路径配置
is only applied during the “Main” phase. It may allow to customize Python in Python to override or tune the
路径配置
, maybe install a custom
sys.meta_path
importer or an import hook, etc.
It may become possible to calculatin the 路径配置 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);
}
}