mirror of https://github.com/python/cpython
404 lines
16 KiB
ReStructuredText
404 lines
16 KiB
ReStructuredText
.. highlight:: c
|
|
|
|
.. _os:
|
|
|
|
Operating System Utilities
|
|
==========================
|
|
|
|
.. c:function:: PyObject* PyOS_FSPath(PyObject *path)
|
|
|
|
Return the file system representation for *path*. If the object is a
|
|
:class:`str` or :class:`bytes` object, then its reference count is
|
|
incremented. If the object implements the :class:`os.PathLike` interface,
|
|
then :meth:`~os.PathLike.__fspath__` is returned as long as it is a
|
|
:class:`str` or :class:`bytes` object. Otherwise :exc:`TypeError` is raised
|
|
and ``NULL`` is returned.
|
|
|
|
.. versionadded:: 3.6
|
|
|
|
|
|
.. c:function:: int Py_FdIsInteractive(FILE *fp, const char *filename)
|
|
|
|
Return true (nonzero) if the standard I/O file *fp* with name *filename* is
|
|
deemed interactive. This is the case for files for which ``isatty(fileno(fp))``
|
|
is true. If the :c:member:`PyConfig.interactive` is non-zero, this function
|
|
also returns true if the *filename* pointer is ``NULL`` or if the name is equal to
|
|
one of the strings ``'<stdin>'`` or ``'???'``.
|
|
|
|
This function must not be called before Python is initialized.
|
|
|
|
|
|
.. c:function:: void PyOS_BeforeFork()
|
|
|
|
Function to prepare some internal state before a process fork. This
|
|
should be called before calling :c:func:`fork` or any similar function
|
|
that clones the current process.
|
|
Only available on systems where :c:func:`fork` is defined.
|
|
|
|
.. warning::
|
|
The C :c:func:`fork` call should only be made from the
|
|
:ref:`"main" thread <fork-and-threads>` (of the
|
|
:ref:`"main" interpreter <sub-interpreter-support>`). The same is
|
|
true for ``PyOS_BeforeFork()``.
|
|
|
|
.. versionadded:: 3.7
|
|
|
|
|
|
.. c:function:: void PyOS_AfterFork_Parent()
|
|
|
|
Function to update some internal state after a process fork. This
|
|
should be called from the parent process after calling :c:func:`fork`
|
|
or any similar function that clones the current process, regardless
|
|
of whether process cloning was successful.
|
|
Only available on systems where :c:func:`fork` is defined.
|
|
|
|
.. warning::
|
|
The C :c:func:`fork` call should only be made from the
|
|
:ref:`"main" thread <fork-and-threads>` (of the
|
|
:ref:`"main" interpreter <sub-interpreter-support>`). The same is
|
|
true for ``PyOS_AfterFork_Parent()``.
|
|
|
|
.. versionadded:: 3.7
|
|
|
|
|
|
.. c:function:: void PyOS_AfterFork_Child()
|
|
|
|
Function to update internal interpreter state after a process fork.
|
|
This must be called from the child process after calling :c:func:`fork`,
|
|
or any similar function that clones the current process, if there is
|
|
any chance the process will call back into the Python interpreter.
|
|
Only available on systems where :c:func:`fork` is defined.
|
|
|
|
.. warning::
|
|
The C :c:func:`fork` call should only be made from the
|
|
:ref:`"main" thread <fork-and-threads>` (of the
|
|
:ref:`"main" interpreter <sub-interpreter-support>`). The same is
|
|
true for ``PyOS_AfterFork_Child()``.
|
|
|
|
.. versionadded:: 3.7
|
|
|
|
.. seealso::
|
|
:func:`os.register_at_fork` allows registering custom Python functions
|
|
to be called by :c:func:`PyOS_BeforeFork()`,
|
|
:c:func:`PyOS_AfterFork_Parent` and :c:func:`PyOS_AfterFork_Child`.
|
|
|
|
|
|
.. c:function:: void PyOS_AfterFork()
|
|
|
|
Function to update some internal state after a process fork; this should be
|
|
called in the new process if the Python interpreter will continue to be used.
|
|
If a new executable is loaded into the new process, this function does not need
|
|
to be called.
|
|
|
|
.. deprecated:: 3.7
|
|
This function is superseded by :c:func:`PyOS_AfterFork_Child()`.
|
|
|
|
|
|
.. c:function:: int PyOS_CheckStack()
|
|
|
|
Return true when the interpreter runs out of stack space. This is a reliable
|
|
check, but is only available when :const:`USE_STACKCHECK` is defined (currently
|
|
on certain versions of Windows using the Microsoft Visual C++ compiler).
|
|
:const:`USE_STACKCHECK` will be defined automatically; you should never
|
|
change the definition in your own code.
|
|
|
|
|
|
.. c:function:: PyOS_sighandler_t PyOS_getsig(int i)
|
|
|
|
Return the current signal handler for signal *i*. This is a thin wrapper around
|
|
either :c:func:`sigaction` or :c:func:`signal`. Do not call those functions
|
|
directly! :c:type:`PyOS_sighandler_t` is a typedef alias for :c:expr:`void
|
|
(\*)(int)`.
|
|
|
|
|
|
.. c:function:: PyOS_sighandler_t PyOS_setsig(int i, PyOS_sighandler_t h)
|
|
|
|
Set the signal handler for signal *i* to be *h*; return the old signal handler.
|
|
This is a thin wrapper around either :c:func:`sigaction` or :c:func:`signal`. Do
|
|
not call those functions directly! :c:type:`PyOS_sighandler_t` is a typedef
|
|
alias for :c:expr:`void (\*)(int)`.
|
|
|
|
.. c:function:: wchar_t* Py_DecodeLocale(const char* arg, size_t *size)
|
|
|
|
.. warning::
|
|
This function should not be called directly: use the :c:type:`PyConfig`
|
|
API with the :c:func:`PyConfig_SetBytesString` function which ensures
|
|
that :ref:`Python is preinitialized <c-preinit>`.
|
|
|
|
This function must not be called before :ref:`Python is preinitialized
|
|
<c-preinit>` and so that the LC_CTYPE locale is properly configured: see
|
|
the :c:func:`Py_PreInitialize` function.
|
|
|
|
Decode a byte string from the :term:`filesystem encoding and error handler`.
|
|
If the error handler is :ref:`surrogateescape error handler
|
|
<surrogateescape>`, undecodable bytes are decoded as characters in range
|
|
U+DC80..U+DCFF; and if a byte sequence can be decoded as a surrogate
|
|
character, the bytes are escaped using the surrogateescape error handler
|
|
instead of decoding them.
|
|
|
|
Return a pointer to a newly allocated wide character string, use
|
|
:c:func:`PyMem_RawFree` to free the memory. If size is not ``NULL``, write
|
|
the number of wide characters excluding the null character into ``*size``
|
|
|
|
Return ``NULL`` on decoding error or memory allocation error. If *size* is
|
|
not ``NULL``, ``*size`` is set to ``(size_t)-1`` on memory error or set to
|
|
``(size_t)-2`` on decoding error.
|
|
|
|
The :term:`filesystem encoding and error handler` are selected by
|
|
:c:func:`PyConfig_Read`: see :c:member:`~PyConfig.filesystem_encoding` and
|
|
:c:member:`~PyConfig.filesystem_errors` members of :c:type:`PyConfig`.
|
|
|
|
Decoding errors should never happen, unless there is a bug in the C
|
|
library.
|
|
|
|
Use the :c:func:`Py_EncodeLocale` function to encode the character string
|
|
back to a byte string.
|
|
|
|
.. seealso::
|
|
|
|
The :c:func:`PyUnicode_DecodeFSDefaultAndSize` and
|
|
:c:func:`PyUnicode_DecodeLocaleAndSize` functions.
|
|
|
|
.. versionadded:: 3.5
|
|
|
|
.. versionchanged:: 3.7
|
|
The function now uses the UTF-8 encoding in the :ref:`Python UTF-8 Mode
|
|
<utf8-mode>`.
|
|
|
|
.. versionchanged:: 3.8
|
|
The function now uses the UTF-8 encoding on Windows if
|
|
:c:member:`PyConfig.legacy_windows_fs_encoding` is zero;
|
|
|
|
|
|
.. c:function:: char* Py_EncodeLocale(const wchar_t *text, size_t *error_pos)
|
|
|
|
Encode a wide character string to the :term:`filesystem encoding and error
|
|
handler`. If the error handler is :ref:`surrogateescape error handler
|
|
<surrogateescape>`, surrogate characters in the range U+DC80..U+DCFF are
|
|
converted to bytes 0x80..0xFF.
|
|
|
|
Return a pointer to a newly allocated byte string, use :c:func:`PyMem_Free`
|
|
to free the memory. Return ``NULL`` on encoding error or memory allocation
|
|
error.
|
|
|
|
If error_pos is not ``NULL``, ``*error_pos`` is set to ``(size_t)-1`` on
|
|
success, or set to the index of the invalid character on encoding error.
|
|
|
|
The :term:`filesystem encoding and error handler` are selected by
|
|
:c:func:`PyConfig_Read`: see :c:member:`~PyConfig.filesystem_encoding` and
|
|
:c:member:`~PyConfig.filesystem_errors` members of :c:type:`PyConfig`.
|
|
|
|
Use the :c:func:`Py_DecodeLocale` function to decode the bytes string back
|
|
to a wide character string.
|
|
|
|
.. warning::
|
|
This function must not be called before :ref:`Python is preinitialized
|
|
<c-preinit>` and so that the LC_CTYPE locale is properly configured: see
|
|
the :c:func:`Py_PreInitialize` function.
|
|
|
|
.. seealso::
|
|
|
|
The :c:func:`PyUnicode_EncodeFSDefault` and
|
|
:c:func:`PyUnicode_EncodeLocale` functions.
|
|
|
|
.. versionadded:: 3.5
|
|
|
|
.. versionchanged:: 3.7
|
|
The function now uses the UTF-8 encoding in the :ref:`Python UTF-8 Mode
|
|
<utf8-mode>`.
|
|
|
|
.. versionchanged:: 3.8
|
|
The function now uses the UTF-8 encoding on Windows if
|
|
:c:member:`PyConfig.legacy_windows_fs_encoding` is zero.
|
|
|
|
|
|
.. _systemfunctions:
|
|
|
|
System Functions
|
|
================
|
|
|
|
These are utility functions that make functionality from the :mod:`sys` module
|
|
accessible to C code. They all work with the current interpreter thread's
|
|
:mod:`sys` module's dict, which is contained in the internal thread state structure.
|
|
|
|
.. c:function:: PyObject *PySys_GetObject(const char *name)
|
|
|
|
Return the object *name* from the :mod:`sys` module or ``NULL`` if it does
|
|
not exist, without setting an exception.
|
|
|
|
.. c:function:: int PySys_SetObject(const char *name, PyObject *v)
|
|
|
|
Set *name* in the :mod:`sys` module to *v* unless *v* is ``NULL``, in which
|
|
case *name* is deleted from the sys module. Returns ``0`` on success, ``-1``
|
|
on error.
|
|
|
|
.. c:function:: void PySys_ResetWarnOptions()
|
|
|
|
Reset :data:`sys.warnoptions` to an empty list. This function may be
|
|
called prior to :c:func:`Py_Initialize`.
|
|
|
|
.. deprecated-removed:: 3.13 3.15
|
|
Clear :data:`sys.warnoptions` and :data:`!warnings.filters` instead.
|
|
|
|
.. c:function:: void PySys_WriteStdout(const char *format, ...)
|
|
|
|
Write the output string described by *format* to :data:`sys.stdout`. No
|
|
exceptions are raised, even if truncation occurs (see below).
|
|
|
|
*format* should limit the total size of the formatted output string to
|
|
1000 bytes or less -- after 1000 bytes, the output string is truncated.
|
|
In particular, this means that no unrestricted "%s" formats should occur;
|
|
these should be limited using "%.<N>s" where <N> is a decimal number
|
|
calculated so that <N> plus the maximum size of other formatted text does not
|
|
exceed 1000 bytes. Also watch out for "%f", which can print hundreds of
|
|
digits for very large numbers.
|
|
|
|
If a problem occurs, or :data:`sys.stdout` is unset, the formatted message
|
|
is written to the real (C level) *stdout*.
|
|
|
|
.. c:function:: void PySys_WriteStderr(const char *format, ...)
|
|
|
|
As :c:func:`PySys_WriteStdout`, but write to :data:`sys.stderr` or *stderr*
|
|
instead.
|
|
|
|
.. c:function:: void PySys_FormatStdout(const char *format, ...)
|
|
|
|
Function similar to PySys_WriteStdout() but format the message using
|
|
:c:func:`PyUnicode_FromFormatV` and don't truncate the message to an
|
|
arbitrary length.
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
.. c:function:: void PySys_FormatStderr(const char *format, ...)
|
|
|
|
As :c:func:`PySys_FormatStdout`, but write to :data:`sys.stderr` or *stderr*
|
|
instead.
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
.. c:function:: PyObject *PySys_GetXOptions()
|
|
|
|
Return the current dictionary of :option:`-X` options, similarly to
|
|
:data:`sys._xoptions`. On error, ``NULL`` is returned and an exception is
|
|
set.
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
|
|
.. c:function:: int PySys_Audit(const char *event, const char *format, ...)
|
|
|
|
Raise an auditing event with any active hooks. Return zero for success
|
|
and non-zero with an exception set on failure.
|
|
|
|
If any hooks have been added, *format* and other arguments will be used
|
|
to construct a tuple to pass. Apart from ``N``, the same format characters
|
|
as used in :c:func:`Py_BuildValue` are available. If the built value is not
|
|
a tuple, it will be added into a single-element tuple. (The ``N`` format
|
|
option consumes a reference, but since there is no way to know whether
|
|
arguments to this function will be consumed, using it may cause reference
|
|
leaks.)
|
|
|
|
Note that ``#`` format characters should always be treated as
|
|
:c:type:`Py_ssize_t`, regardless of whether ``PY_SSIZE_T_CLEAN`` was defined.
|
|
|
|
:func:`sys.audit` performs the same function from Python code.
|
|
|
|
.. versionadded:: 3.8
|
|
|
|
.. versionchanged:: 3.8.2
|
|
|
|
Require :c:type:`Py_ssize_t` for ``#`` format characters. Previously, an
|
|
unavoidable deprecation warning was raised.
|
|
|
|
|
|
.. c:function:: int PySys_AddAuditHook(Py_AuditHookFunction hook, void *userData)
|
|
|
|
Append the callable *hook* to the list of active auditing hooks.
|
|
Return zero on success
|
|
and non-zero on failure. If the runtime has been initialized, also set an
|
|
error on failure. Hooks added through this API are called for all
|
|
interpreters created by the runtime.
|
|
|
|
The *userData* pointer is passed into the hook function. Since hook
|
|
functions may be called from different runtimes, this pointer should not
|
|
refer directly to Python state.
|
|
|
|
This function is safe to call before :c:func:`Py_Initialize`. When called
|
|
after runtime initialization, existing audit hooks are notified and may
|
|
silently abort the operation by raising an error subclassed from
|
|
:class:`Exception` (other errors will not be silenced).
|
|
|
|
The hook function is of type :c:expr:`int (*)(const char *event, PyObject
|
|
*args, void *userData)`, where *args* is guaranteed to be a
|
|
:c:type:`PyTupleObject`. The hook function is always called with the GIL
|
|
held by the Python interpreter that raised the event.
|
|
|
|
See :pep:`578` for a detailed description of auditing. Functions in the
|
|
runtime and standard library that raise events are listed in the
|
|
:ref:`audit events table <audit-events>`.
|
|
Details are in each function's documentation.
|
|
|
|
.. audit-event:: sys.addaudithook "" c.PySys_AddAuditHook
|
|
|
|
If the interpreter is initialized, this function raises a auditing event
|
|
``sys.addaudithook`` with no arguments. If any existing hooks raise an
|
|
exception derived from :class:`Exception`, the new hook will not be
|
|
added and the exception is cleared. As a result, callers cannot assume
|
|
that their hook has been added unless they control all existing hooks.
|
|
|
|
.. versionadded:: 3.8
|
|
|
|
|
|
.. _processcontrol:
|
|
|
|
Process Control
|
|
===============
|
|
|
|
|
|
.. c:function:: void Py_FatalError(const char *message)
|
|
|
|
.. index:: single: abort()
|
|
|
|
Print a fatal error message and kill the process. No cleanup is performed.
|
|
This function should only be invoked when a condition is detected that would
|
|
make it dangerous to continue using the Python interpreter; e.g., when the
|
|
object administration appears to be corrupted. On Unix, the standard C library
|
|
function :c:func:`abort` is called which will attempt to produce a :file:`core`
|
|
file.
|
|
|
|
The ``Py_FatalError()`` function is replaced with a macro which logs
|
|
automatically the name of the current function, unless the
|
|
``Py_LIMITED_API`` macro is defined.
|
|
|
|
.. versionchanged:: 3.9
|
|
Log the function name automatically.
|
|
|
|
|
|
.. c:function:: void Py_Exit(int status)
|
|
|
|
.. index::
|
|
single: Py_FinalizeEx()
|
|
single: exit()
|
|
|
|
Exit the current process. This calls :c:func:`Py_FinalizeEx` and then calls the
|
|
standard C library function ``exit(status)``. If :c:func:`Py_FinalizeEx`
|
|
indicates an error, the exit status is set to 120.
|
|
|
|
.. versionchanged:: 3.6
|
|
Errors from finalization no longer ignored.
|
|
|
|
|
|
.. c:function:: int Py_AtExit(void (*func) ())
|
|
|
|
.. index::
|
|
single: Py_FinalizeEx()
|
|
single: cleanup functions
|
|
|
|
Register a cleanup function to be called by :c:func:`Py_FinalizeEx`. The cleanup
|
|
function will be called with no arguments and should return no value. At most
|
|
32 cleanup functions can be registered. When the registration is successful,
|
|
:c:func:`Py_AtExit` returns ``0``; on failure, it returns ``-1``. The cleanup
|
|
function registered last is called first. Each cleanup function will be called
|
|
at most once. Since Python's internal finalization will have completed before
|
|
the cleanup function, no Python APIs should be called by *func*.
|