Python Initialization Configuration¶
Nouveau dans la version 3.8.
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.
See also Initialization, Finalization, and Threads.
Voir aussi
PEP 587 "Python Initialization Configuration".
Example¶
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¶
List of
wchar_t*
strings.If length is non-zero, items must be non-
NULL
and all strings must be non-NULL
.Methods:
-
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¶
List length.
-
wchar_t **items¶
List items.
-
PyStatus PyWideStringList_Append(PyWideStringList *list, const wchar_t *item)¶
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¶
Error message.
-
const char *func¶
Name of the function which created an error, can be
NULL
.
Functions to create a status:
-
PyStatus PyStatus_Error(const char *err_msg)¶
Initialization error with a message.
err_msg must not be
NULL
.
Functions to handle a status:
-
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 exitcode¶
Note
Internally, Python uses macros which set PyStatus.func
,
whereas functions to create a status set func
to NULL
.
Exemple :
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
): usemalloc()
of the C library.PYMEM_ALLOCATOR_MALLOC_DEBUG
(4
): force usage ofmalloc()
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
andPYMEM_ALLOCATOR_PYMALLOC_DEBUG
are not supported if Python isconfigured using --without-pymalloc
.See Memory Management.
Default:
PYMEM_ALLOCATOR_NOT_SET
.
-
int configure_locale¶
Set the LC_CTYPE locale to the user preferred locale.
If equals to
0
, setcoerce_c_locale
andcoerce_c_locale_warn
members to0
.See the 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.See the 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¶
If non-zero:
Set
PyPreConfig.utf8_mode
to0
,Set
PyConfig.filesystem_encoding
to"mbcs"
,Set
PyConfig.filesystem_errors
to"replace"
.
Initialized the from
PYTHONLEGACYWINDOWSFSENCODING
environment variable value.Only available on Windows.
#ifdef MS_WINDOWS
macro can be used for Windows specific code.Default:
0
.
-
int parse_argv¶
If non-zero,
Py_PreInitializeFromArgs()
andPy_PreInitializeFromBytesArgs()
parse theirargv
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 and0
in isolated config.
-
int utf8_mode¶
If non-zero, enable the Python UTF-8 Mode.
Set to
0
or1
by the-X utf8
command line option and thePYTHONUTF8
environment variable.Also set to
1
if theLC_CTYPE
locale isC
orPOSIX
.Default:
-1
in Python config and0
in isolated config.
-
void PyPreConfig_InitPythonConfig(PyPreConfig *preconfig)¶
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 must not be
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 must not be
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 must not be
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 usingPy_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 list to length and items.
Preinitialize Python if needed.
-
PyStatus PyConfig_Read(PyConfig *config)¶
Read all Python configuration.
Fields which are already initialized are left unchanged.
Fields for path configuration are no longer calculated or modified when calling this function, as of Python 3.11.
The
PyConfig_Read()
function only parsesPyConfig.argv
arguments once:PyConfig.parse_argv
is set to2
after arguments are parsed. Since Python arguments are strippped fromPyConfig.argv
, parsing arguments twice would parse the application options as Python options.Preinitialize Python if needed.
Modifié dans la version 3.10: The
PyConfig.argv
arguments are now only parsed once,PyConfig.parse_argv
is set to2
after arguments are parsed, and arguments are only parsed ifPyConfig.parse_argv
equals1
.Modifié dans la version 3.11:
PyConfig_Read()
no longer calculates all paths, and so fields listed under Python Path Configuration may no longer be updated untilPy_InitializeFromConfig()
is called.
Most
PyConfig
methods preinitialize Python if needed. In that case, the Python preinitialization configuration (PyPreConfig
) 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 before other methods, since the preinitialization configuration depends on command line arguments (ifparse_argv
is non-zero).The caller of these methods is responsible to handle exceptions (error or exit) using
PyStatus_Exception()
andPy_ExitStatusException()
.Structure fields:
-
PyWideStringList argv¶
Command line arguments:
sys.argv
.Set
parse_argv
to1
to parseargv
the same way the regular Python parses Python command line arguments and then to strip Python arguments fromargv
.If
argv
is empty, an empty string is added to ensure thatsys.argv
always exists and is never empty.Default:
NULL
.See also the
orig_argv
member.
-
int safe_path¶
If equals to zero,
Py_RunMain()
prepends a potentially unsafe path tosys.path
at startup:If
argv[0]
is equal toL"-m"
(python -m module
), prepend the current working directory.If running a script (
python script.py
), prepend the script's directory. If it's a symbolic link, resolve symbolic links.Otherwise (
python -c code
andpython
), prepend an empty string, which means the current working directory.
Set to
1
by the-P
command line option and thePYTHONSAFEPATH
environment variable.Default:
0
in Python config,1
in isolated config.Nouveau dans la version 3.11.
-
wchar_t *base_exec_prefix¶
-
Default:
NULL
.Part of the Python Path Configuration output.
-
wchar_t *base_executable¶
Python base executable:
sys._base_executable
.Set by the
__PYVENV_LAUNCHER__
environment variable.Set from
PyConfig.executable
ifNULL
.Default:
NULL
.Part of the Python Path Configuration output.
-
wchar_t *base_prefix¶
-
Default:
NULL
.Part of the Python Path Configuration output.
-
int buffered_stdio¶
If equals to
0
andconfigure_c_stdio
is non-zero, disable buffering on the C streams stdout and stderr.Set to
0
by the-u
command line option and thePYTHONUNBUFFERED
environment variable.stdin is always opened in buffered mode.
Default:
1
.
-
int bytes_warning¶
If equals to
1
, issue a warning when comparingbytes
orbytearray
withstr
, or comparingbytes
withint
.If equal or greater to
2
, raise aBytesWarning
exception in these cases.Incremented by the
-b
command line option.Default:
0
.
-
int warn_default_encoding¶
If non-zero, emit a
EncodingWarning
warning whenio.TextIOWrapper
uses its default encoding. See Opt-in EncodingWarning for details.Default:
0
.Nouveau dans la version 3.10.
-
int code_debug_ranges¶
If equals to
0
, disables the inclusion of the end line and column mappings in code objects. Also disables traceback printing carets to specific error locations.Set to
0
by thePYTHONNODEBUGRANGES
environment variable and by the-X no_debug_ranges
command line option.Default:
1
.Nouveau dans la version 3.11.
-
wchar_t *check_hash_pycs_mode¶
Control the validation behavior of hash-based
.pyc
files: value of the--check-hash-based-pycs
command line option.Valid values:
L"always"
: Hash the source file for invalidation regardless of value of the 'check_source' flag.L"never"
: Assume that hash-based pycs always are valid.L"default"
: The 'check_source' flag in hash-based pycs determines invalidation.
Default:
L"default"
.See also PEP 552 "Deterministic pycs".
-
int configure_c_stdio¶
If non-zero, configure C standard streams:
On Windows, set the binary mode (
O_BINARY
) on stdin, stdout and stderr.If
buffered_stdio
equals zero, disable buffering of stdin, stdout and stderr streams.If
interactive
is non-zero, enable stream buffering on stdin and stdout (only stdout on Windows).
Default:
1
in Python config,0
in isolated config.
-
int dev_mode¶
If non-zero, enable the Python Development Mode.
Set to
1
by the-X dev
option and thePYTHONDEVMODE
environment variable.Default:
-1
in Python mode,0
in isolated mode.
-
int dump_refs¶
Dump Python references?
If non-zero, dump all objects which are still alive at exit.
Set to
1
by thePYTHONDUMPREFS
environment variable.Need a special build of Python with the
Py_TRACE_REFS
macro defined: see theconfigure --with-trace-refs option
.Default:
0
.
-
wchar_t *exec_prefix¶
The site-specific directory prefix where the platform-dependent Python files are installed:
sys.exec_prefix
.Default:
NULL
.Part of the Python Path Configuration output.
-
wchar_t *executable¶
The absolute path of the executable binary for the Python interpreter:
sys.executable
.Default:
NULL
.Part of the Python Path Configuration output.
-
int faulthandler¶
Enable faulthandler?
If non-zero, call
faulthandler.enable()
at startup.Set to
1
by-X faulthandler
and thePYTHONFAULTHANDLER
environment variable.Default:
-1
in Python mode,0
in isolated mode.
-
wchar_t *filesystem_encoding¶
Filesystem encoding:
sys.getfilesystemencoding()
.On macOS, Android and VxWorks: use
"utf-8"
by default.On Windows: use
"utf-8"
by default, or"mbcs"
iflegacy_windows_fs_encoding
ofPyPreConfig
is non-zero.Default encoding on other platforms:
"utf-8"
ifPyPreConfig.utf8_mode
is non-zero."ascii"
if Python detects thatnl_langinfo(CODESET)
announces the ASCII encoding, whereas thembstowcs()
function decodes from a different encoding (usually Latin1)."utf-8"
ifnl_langinfo(CODESET)
returns an empty string.Otherwise, use the locale encoding:
nl_langinfo(CODESET)
result.
At Python startup, the encoding name is normalized to the Python codec name. For example,
"ANSI_X3.4-1968"
is replaced with"ascii"
.See also the
filesystem_errors
member.
-
wchar_t *filesystem_errors¶
Filesystem error handler:
sys.getfilesystemencodeerrors()
.On Windows: use
"surrogatepass"
by default, or"replace"
iflegacy_windows_fs_encoding
ofPyPreConfig
is non-zero.On other platforms: use
"surrogateescape"
by default.Supported error handlers:
"strict"
"surrogateescape"
"surrogatepass"
(only supported with the UTF-8 encoding)
See also the
filesystem_encoding
member.
-
unsigned long hash_seed¶
-
int use_hash_seed¶
Randomized hash function seed.
If
use_hash_seed
is zero, a seed is chosen randomly at Python startup, andhash_seed
is ignored.Set by the
PYTHONHASHSEED
environment variable.Default use_hash_seed value:
-1
in Python mode,0
in isolated mode.
-
wchar_t *home¶
Python home directory.
If
Py_SetPythonHome()
has been called, use its argument if it is notNULL
.Set by the
PYTHONHOME
environment variable.Default:
NULL
.Part of the Python Path Configuration input.
-
int import_time¶
If non-zero, profile import time.
Set the
1
by the-X importtime
option and thePYTHONPROFILEIMPORTTIME
environment variable.Default:
0
.
-
int inspect¶
Enter interactive mode after executing a script or a command.
If greater than
0
, enable inspect: when a script is passed as first argument or the -c option is used, enter interactive mode after executing the script or the command, even whensys.stdin
does not appear to be a terminal.Incremented by the
-i
command line option. Set to1
if thePYTHONINSPECT
environment variable is non-empty.Default:
0
.
-
int install_signal_handlers¶
Install Python signal handlers?
Default:
1
in Python mode,0
in isolated mode.
-
int interactive¶
If greater than
0
, enable the interactive mode (REPL).Incremented by the
-i
command line option.Default:
0
.
-
int isolated¶
If greater than
0
, enable isolated mode:Set
safe_path
to1
: don't prepend a potentially unsafe path tosys.path
at Python startup.Set
use_environment
to0
.Set
user_site_directory
to0
: don't add the user site directory tosys.path
.Python REPL doesn't import
readline
nor enable default readline configuration on interactive prompts.
Set to
1
by the-I
command line option.Default:
0
in Python mode,1
in isolated mode.See also
PyPreConfig.isolated
.
-
int legacy_windows_stdio¶
If non-zero, use
io.FileIO
instead ofio._WindowsConsoleIO
forsys.stdin
,sys.stdout
andsys.stderr
.Set to
1
if thePYTHONLEGACYWINDOWSSTDIO
environment variable is set to a non-empty string.Only available on Windows.
#ifdef MS_WINDOWS
macro can be used for Windows specific code.Default:
0
.See also the PEP 528 (Change Windows console encoding to UTF-8).
-
int malloc_stats¶
If non-zero, dump statistics on Python pymalloc memory allocator at exit.
Set to
1
by thePYTHONMALLOCSTATS
environment variable.The option is ignored if Python is
configured using the --without-pymalloc option
.Default:
0
.
-
wchar_t *platlibdir¶
Platform library directory name:
sys.platlibdir
.Set by the
PYTHONPLATLIBDIR
environment variable.Default: value of the
PLATLIBDIR
macro which is set by theconfigure --with-platlibdir option
(default:"lib"
, or"DLLs"
on Windows).Part of the Python Path Configuration input.
Nouveau dans la version 3.9.
Modifié dans la version 3.11: This macro is now used on Windows to locate the standard library extension modules, typically under
DLLs
. However, for compatibility, note that this value is ignored for any non-standard layouts, including in-tree builds and virtual environments.
-
wchar_t *pythonpath_env¶
Module search paths (
sys.path
) as a string separated byDELIM
(os.pathsep
).Set by the
PYTHONPATH
environment variable.Default:
NULL
.Part of the Python Path Configuration input.
-
PyWideStringList module_search_paths¶
-
int module_search_paths_set¶
Module search paths:
sys.path
.If
module_search_paths_set
is equal to0
,Py_InitializeFromConfig()
will replacemodule_search_paths
and setsmodule_search_paths_set
to1
.Default: empty list (
module_search_paths
) and0
(module_search_paths_set
).Part of the Python Path Configuration output.
-
int optimization_level¶
Compilation optimization level:
0
: Peephole optimizer, set__debug__
toTrue
.1
: Level 0, remove assertions, set__debug__
toFalse
.2
: Level 1, strip docstrings.
Incremented by the
-O
command line option. Set to thePYTHONOPTIMIZE
environment variable value.Default:
0
.
-
PyWideStringList orig_argv¶
The list of the original command line arguments passed to the Python executable:
sys.orig_argv
.If
orig_argv
list is empty andargv
is not a list only containing an empty string,PyConfig_Read()
copiesargv
intoorig_argv
before modifyingargv
(ifparse_argv
is non-zero).See also the
argv
member and thePy_GetArgcArgv()
function.Default: empty list.
Nouveau dans la version 3.10.
-
int parse_argv¶
Parse command line arguments?
If equals to
1
, parseargv
the same way the regular Python parses command line arguments, and strip Python arguments fromargv
.The
PyConfig_Read()
function only parsesPyConfig.argv
arguments once:PyConfig.parse_argv
is set to2
after arguments are parsed. Since Python arguments are strippped fromPyConfig.argv
, parsing arguments twice would parse the application options as Python options.Default:
1
in Python mode,0
in isolated mode.Modifié dans la version 3.10: The
PyConfig.argv
arguments are now only parsed ifPyConfig.parse_argv
equals to1
.
-
int parser_debug¶
Parser debug mode. If greater than
0
, turn on parser debugging output (for expert only, depending on compilation options).Incremented by the
-d
command line option. Set to thePYTHONDEBUG
environment variable value.Default:
0
.
-
int pathconfig_warnings¶
If non-zero, calculation of path configuration is allowed to log warnings into
stderr
. If equals to0
, suppress these warnings.Default:
1
in Python mode,0
in isolated mode.Part of the Python Path Configuration input.
Modifié dans la version 3.11: Now also applies on Windows.
-
wchar_t *prefix¶
The site-specific directory prefix where the platform independent Python files are installed:
sys.prefix
.Default:
NULL
.Part of the Python Path Configuration output.
-
wchar_t *program_name¶
Program name used to initialize
executable
and in early error messages during Python initialization.If
Py_SetProgramName()
has been called, use its argument.On macOS, use
PYTHONEXECUTABLE
environment variable if set.If the
WITH_NEXT_FRAMEWORK
macro is defined, use__PYVENV_LAUNCHER__
environment variable if set.Use
argv[0]
ofargv
if available and non-empty.Otherwise, use
L"python"
on Windows, orL"python3"
on other platforms.
Default:
NULL
.Part of the Python Path Configuration input.
-
wchar_t *pycache_prefix¶
Directory where cached
.pyc
files are written:sys.pycache_prefix
.Set by the
-X pycache_prefix=PATH
command line option and thePYTHONPYCACHEPREFIX
environment variable.If
NULL
,sys.pycache_prefix
is set toNone
.Default:
NULL
.
-
int quiet¶
Quiet mode. If greater than
0
, don't display the copyright and version at Python startup in interactive mode.Incremented by the
-q
command line option.Default:
0
.
-
wchar_t *run_command¶
Value of the
-c
command line option.Used by
Py_RunMain()
.Default:
NULL
.
-
wchar_t *run_filename¶
Filename passed on the command line: trailing command line argument without
-c
or-m
. It is used by thePy_RunMain()
function.For example, it is set to
script.py
by thepython3 script.py arg
command line.See also the
PyConfig.skip_source_first_line
option.Default:
NULL
.
-
wchar_t *run_module¶
Value of the
-m
command line option.Used by
Py_RunMain()
.Default:
NULL
.
-
int show_ref_count¶
Show total reference count at exit?
Set to
1
by-X showrefcount
command line option.Need a debug build of Python (the
Py_REF_DEBUG
macro must be defined).Default:
0
.
-
int site_import¶
Import the
site
module at startup?If equal to zero, disable the import of the module site and the site-dependent manipulations of
sys.path
that it entails.Also disable these manipulations if the
site
module is explicitly imported later (callsite.main()
if you want them to be triggered).Set to
0
by the-S
command line option.sys.flags.no_site
is set to the inverted value ofsite_import
.Default:
1
.
-
int skip_source_first_line¶
If non-zero, skip the first line of the
PyConfig.run_filename
source.It allows the usage of non-Unix forms of
#!cmd
. This is intended for a DOS specific hack only.Set to
1
by the-x
command line option.Default:
0
.
-
wchar_t *stdio_encoding¶
-
wchar_t *stdio_errors¶
Encoding and encoding errors of
sys.stdin
,sys.stdout
andsys.stderr
(butsys.stderr
always uses"backslashreplace"
error handler).If
Py_SetStandardStreamEncoding()
has been called, use its error and errors arguments if they are notNULL
.Use the
PYTHONIOENCODING
environment variable if it is non-empty.Default encoding:
"UTF-8"
ifPyPreConfig.utf8_mode
is non-zero.Otherwise, use the locale encoding.
Default error handler:
On Windows: use
"surrogateescape"
."surrogateescape"
ifPyPreConfig.utf8_mode
is non-zero, or if the LC_CTYPE locale is "C" or "POSIX"."strict"
otherwise.
-
int tracemalloc¶
Enable tracemalloc?
If non-zero, call
tracemalloc.start()
at startup.Set by
-X tracemalloc=N
command line option and by thePYTHONTRACEMALLOC
environment variable.Default:
-1
in Python mode,0
in isolated mode.
-
int use_environment¶
-
If equals to zero, ignore the environment variables.
Set to
0
by the-E
environment variable.Default:
1
in Python config and0
in isolated config.
-
int user_site_directory¶
If non-zero, add the user site directory to
sys.path
.Set to
0
by the-s
and-I
command line options.Set to
0
by thePYTHONNOUSERSITE
environment variable.Default:
1
in Python mode,0
in isolated mode.
-
int verbose¶
Verbose mode. If greater than
0
, print a message each time a module is imported, showing the place (filename or built-in module) from which it is loaded.If greater or equal to
2
, print a message for each file that is checked for when searching for a module. Also provides information on module cleanup at exit.Incremented by the
-v
command line option.Set to the
PYTHONVERBOSE
environment variable value.Default:
0
.
-
PyWideStringList warnoptions¶
Options of the
warnings
module to build warnings filters, lowest to highest priority:sys.warnoptions
.The
warnings
module addssys.warnoptions
in the reverse order: the lastPyConfig.warnoptions
item becomes the first item ofwarnings.filters
which is checked first (highest priority).The
-W
command line options adds its value towarnoptions
, it can be used multiple times.The
PYTHONWARNINGS
environment variable can also be used to add warning options. Multiple options can be specified, separated by commas (,
).Default: empty list.
-
int write_bytecode¶
If equal to
0
, Python won't try to write.pyc
files on the import of source modules.Set to
0
by the-B
command line option and thePYTHONDONTWRITEBYTECODE
environment variable.sys.dont_write_bytecode
is initialized to the inverted value ofwrite_bytecode
.Default:
1
.
-
PyWideStringList xoptions¶
Values of the
-X
command line options:sys._xoptions
.Default: empty list.
-
void PyConfig_InitPythonConfig(PyConfig *config)¶
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
.
The xoptions
options are parsed to set other options: see
the -X
command line option.
Modifié dans la version 3.9: The show_alloc_count
field has been removed.
Initialization with PyConfig¶
Function to initialize Python:
-
PyStatus 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()
.
If 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.
The current configuration (PyConfig
type) is stored in
PyInterpreterState.config
.
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 exception;
}
status = Py_InitializeFromConfig(&config);
if (PyStatus_Exception(status)) {
goto exception;
}
PyConfig_Clear(&config);
return;
exception:
PyConfig_Clear(&config);
Py_ExitStatusException(status);
}
More complete example modifying the default configuration, read the configuration, and then override some parameters. Note that since 3.11, many parameters are not calculated until initialization, and so values cannot be read from the configuration structure. Any values set before initialize is called will be left unchanged by initialization:
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;
}
/* Specify sys.path explicitly */
/* If you want to modify the default set of paths, finish
initialization first and then use PySys_GetObject("path") */
config.module_search_paths_set = 1;
status = PyWideStringList_Append(&config.module_search_paths,
L"/path/to/stdlib");
if (PyStatus_Exception(status)) {
goto done;
}
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;
}
Isolated Configuration¶
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, environment
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 to determine
paths that are unspecified. Ensure PyConfig.home
is specified
to avoid computing the default path configuration.
Python 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 Python UTF-8 Mode
(PEP 540) depending on the LC_CTYPE locale, PYTHONUTF8
and
PYTHONCOERCECLOCALE
environment variables.
Python Path Configuration¶
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 (fromPyConfig.program_name
)__PYVENV_LAUNCHER__
environment variable(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
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,
module_search_paths
will be used without modification.
Set pathconfig_warnings
to 0
to suppress warnings when
calculating the path configuration (Unix only, Windows does not log any warning).
If base_prefix
or base_exec_prefix
fields are not set, they inherit their value from prefix
and exec_prefix
respectively.
Py_RunMain()
and Py_Main()
modify sys.path
:
If
run_filename
is set and is a directory which contains a__main__.py
script, prependrun_filename
tosys.path
.If
isolated
is zero:If
run_module
is set, prepend the current directory tosys.path
. Do nothing if the current directory cannot be read.If
run_filename
is set, prepend the directory of the filename tosys.path
.Otherwise, prepend an empty string to
sys.path
.
If 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
._pth
file (ex:python._pth
)pybuilddir.txt
(Unix only)
If a ._pth
file is present:
Set
isolated
to1
.Set
use_environment
to0
.Set
site_import
to0
.Set
safe_path
to1
.
The __PYVENV_LAUNCHER__
environment variable is used to set
PyConfig.base_executable
Py_RunMain()¶
-
int 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()
function.
See Python Configuration for an example of
customized Python always running in isolated mode using
Py_RunMain()
.
Py_GetArgcArgv()¶
-
void Py_GetArgcArgv(int *argc, wchar_t ***argv)¶
Get the original command line arguments, before Python modified them.
See also
PyConfig.orig_argv
member.
Multi-Phase Initialization Private Provisional API¶
This section is a private provisional API introducing multi-phase initialization, the core feature of PEP 432:
"Core" initialization phase, "bare minimum Python":
"Main" initialization phase, Python is fully initialized:
Install and configure
importlib
;Apply the Path Configuration;
Install signal handlers;
Finish
sys
module initialization (ex: createsys.stdout
andsys.path
);Enable optional features like
faulthandler
andtracemalloc
;Import the
site
module;etc.
Private provisional API:
PyConfig._init_main
: if set to0
,Py_InitializeFromConfig()
stops at the "Core" initialization phase.PyConfig._isolated_interpreter
: if non-zero, disallow threads, subprocesses and fork.
-
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 Path Configuration is only
applied during the "Main" phase. It may allow to customize Python in Python to
override or tune the Path Configuration, maybe
install a custom sys.meta_path
importer or an import hook, etc.
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.
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);
}
}