cpython/Doc/c-api/sys.rst

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.. highlightlang:: c
.. _os:
Operating System Utilities
==========================
.. cfunction:: 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 global flag :cdata:`Py_InteractiveFlag` is true, this function
also returns true if the *filename* pointer is *NULL* or if the name is equal to
one of the strings ``'<stdin>'`` or ``'???'``.
.. cfunction:: 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.
.. cfunction:: 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 Windows using the Microsoft Visual C++ compiler). :const:`USE_STACKCHECK`
will be defined automatically; you should never change the definition in your
own code.
.. cfunction:: PyOS_sighandler_t PyOS_getsig(int i)
Return the current signal handler for signal *i*. This is a thin wrapper around
either :cfunc:`sigaction` or :cfunc:`signal`. Do not call those functions
directly! :ctype:`PyOS_sighandler_t` is a typedef alias for :ctype:`void
(\*)(int)`.
.. cfunction:: 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 :cfunc:`sigaction` or :cfunc:`signal`. Do
not call those functions directly! :ctype:`PyOS_sighandler_t` is a typedef
alias for :ctype:`void (\*)(int)`.
.. _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.
.. cfunction:: PyObject *PySys_GetObject(char *name)
Return the object *name* from the :mod:`sys` module or *NULL* if it does
not exist, without setting an exception.
.. cfunction:: FILE *PySys_GetFile(char *name, FILE *def)
Return the :ctype:`FILE*` associated with the object *name* in the
:mod:`sys` module, or *def* if *name* is not in the module or is not associated
with a :ctype:`FILE*`.
.. cfunction:: int PySys_SetObject(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.
Merged revisions 73941-73943,74076,74094,74186,74211-74214,74247,74254,74262,74311,74334,74368 via svnmerge from svn+ssh://svn.python.org/python/branches/py3k ................ r73941 | georg.brandl | 2009-07-11 12:39:00 +0200 (Sa, 11 Jul 2009) | 9 lines Merged revisions 73940 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r73940 | georg.brandl | 2009-07-11 12:37:38 +0200 (Sa, 11 Jul 2009) | 1 line #6430: add note about size of "u" type. ........ ................ r73942 | georg.brandl | 2009-07-11 12:39:23 +0200 (Sa, 11 Jul 2009) | 1 line #6430: remove mention of "w" array typecode. ................ r73943 | georg.brandl | 2009-07-11 12:43:08 +0200 (Sa, 11 Jul 2009) | 1 line #6421: The self argument of module-level PyCFunctions is now a reference to the module object. ................ r74076 | georg.brandl | 2009-07-18 11:07:48 +0200 (Sa, 18 Jul 2009) | 1 line #6502: add missing comma in docstring. ................ r74094 | georg.brandl | 2009-07-19 09:25:56 +0200 (So, 19 Jul 2009) | 10 lines Recorded merge of revisions 74089 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74089 | senthil.kumaran | 2009-07-19 04:43:43 +0200 (So, 19 Jul 2009) | 3 lines Fix for issue5102, timeout value propages between redirects, proxy, digest and auth handlers. Fixed tests to reflect the same. ........ ................ r74186 | georg.brandl | 2009-07-23 11:19:09 +0200 (Do, 23 Jul 2009) | 9 lines Recorded merge of revisions 74185 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74185 | georg.brandl | 2009-07-23 11:17:09 +0200 (Do, 23 Jul 2009) | 1 line Fix the "pylocals" gdb command. ........ ................ r74211 | georg.brandl | 2009-07-26 16:48:09 +0200 (So, 26 Jul 2009) | 9 lines Recorded merge of revisions 74210 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74210 | georg.brandl | 2009-07-26 16:44:23 +0200 (So, 26 Jul 2009) | 1 line Move member descriptions inside the classes. ........ ................ r74212 | georg.brandl | 2009-07-26 16:54:51 +0200 (So, 26 Jul 2009) | 9 lines Merged revisions 74209 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74209 | georg.brandl | 2009-07-26 16:37:28 +0200 (So, 26 Jul 2009) | 1 line builtin -> built-in. ........ ................ r74213 | georg.brandl | 2009-07-26 17:02:41 +0200 (So, 26 Jul 2009) | 9 lines Merged revisions 74207 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74207 | georg.brandl | 2009-07-26 16:19:57 +0200 (So, 26 Jul 2009) | 1 line #6577: fix (hopefully) all links to builtin instead of module/class-specific objects. ........ ................ r74214 | georg.brandl | 2009-07-26 17:03:49 +0200 (So, 26 Jul 2009) | 9 lines Merged revisions 74205 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74205 | georg.brandl | 2009-07-26 15:36:39 +0200 (So, 26 Jul 2009) | 1 line #6576: fix cross-refs in re docs. ........ ................ r74247 | georg.brandl | 2009-07-29 09:27:08 +0200 (Mi, 29 Jul 2009) | 9 lines Merged revisions 74239 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74239 | georg.brandl | 2009-07-28 18:55:32 +0000 (Di, 28 Jul 2009) | 1 line Clarify quote_plus() usage. ........ ................ r74254 | georg.brandl | 2009-07-29 18:14:16 +0200 (Mi, 29 Jul 2009) | 1 line #6586: fix return/argument type doc for os.read() and os.write(). ................ r74262 | alexandre.vassalotti | 2009-07-29 21:54:39 +0200 (Mi, 29 Jul 2009) | 57 lines Merged revisions 74074,74077,74111,74188,74192-74193,74200,74252-74253,74258-74261 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74074 | georg.brandl | 2009-07-18 05:03:10 -0400 (Sat, 18 Jul 2009) | 1 line #6513: fix example code: warning categories are classes, not instances. ........ r74077 | georg.brandl | 2009-07-18 05:43:40 -0400 (Sat, 18 Jul 2009) | 1 line #6489: fix an ambiguity in getiterator() documentation. ........ r74111 | benjamin.peterson | 2009-07-20 09:30:10 -0400 (Mon, 20 Jul 2009) | 1 line remove docs for deprecated -p option ........ r74188 | benjamin.peterson | 2009-07-23 10:25:31 -0400 (Thu, 23 Jul 2009) | 1 line use bools ........ r74192 | georg.brandl | 2009-07-24 12:28:38 -0400 (Fri, 24 Jul 2009) | 1 line Fix arg types of et#. ........ r74193 | georg.brandl | 2009-07-24 12:46:38 -0400 (Fri, 24 Jul 2009) | 1 line Dont put "void" in signature for nullary functions. ........ r74200 | georg.brandl | 2009-07-25 09:02:15 -0400 (Sat, 25 Jul 2009) | 1 line #6571: add index entries for more operators. ........ r74252 | georg.brandl | 2009-07-29 12:06:31 -0400 (Wed, 29 Jul 2009) | 1 line #6593: fix link targets. ........ r74253 | georg.brandl | 2009-07-29 12:09:17 -0400 (Wed, 29 Jul 2009) | 1 line #6591: add reference to ioctl in fcntl module for platforms other than Windows. ........ r74258 | georg.brandl | 2009-07-29 12:57:05 -0400 (Wed, 29 Jul 2009) | 1 line Add a link to readline, and mention IPython and bpython. ........ r74259 | georg.brandl | 2009-07-29 13:07:21 -0400 (Wed, 29 Jul 2009) | 1 line Fix some markup and small factual glitches found by M. Markert. ........ r74260 | georg.brandl | 2009-07-29 13:15:20 -0400 (Wed, 29 Jul 2009) | 1 line Fix a few markup glitches. ........ r74261 | georg.brandl | 2009-07-29 13:50:25 -0400 (Wed, 29 Jul 2009) | 1 line Rewrite the section about classes a bit; mostly tidbits, and a larger update to the section about "private" variables to reflect the Pythonic consensus better. ........ ................ r74311 | georg.brandl | 2009-08-04 22:29:27 +0200 (Di, 04 Aug 2009) | 1 line Slightly improve buffer-related error message. ................ r74334 | georg.brandl | 2009-08-06 19:51:03 +0200 (Do, 06 Aug 2009) | 1 line #6648: mention surrogateescape handler where all standard handlers are listed. ................ r74368 | georg.brandl | 2009-08-13 09:56:35 +0200 (Do, 13 Aug 2009) | 21 lines Merged revisions 74328,74332-74333,74365 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74328 | georg.brandl | 2009-08-06 17:06:25 +0200 (Do, 06 Aug 2009) | 1 line Fix base keyword arg name for int() and long(). ........ r74332 | georg.brandl | 2009-08-06 19:23:21 +0200 (Do, 06 Aug 2009) | 1 line Fix punctuation and one copy-paste error. ........ r74333 | georg.brandl | 2009-08-06 19:43:55 +0200 (Do, 06 Aug 2009) | 1 line #6658: fix two typos. ........ r74365 | georg.brandl | 2009-08-13 09:48:05 +0200 (Do, 13 Aug 2009) | 1 line #6679: Remove mention that sub supports no flags. ........ ................
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.. cfunction:: void PySys_ResetWarnOptions()
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Reset :data:`sys.warnoptions` to an empty list.
.. cfunction:: void PySys_AddWarnOption(wchar_t *s)
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Append *s* to :data:`sys.warnoptions`.
.. cfunction:: void PySys_SetPath(wchar_t *path)
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Set :data:`sys.path` to a list object of paths found in *path* which should
be a list of paths separated with the platform's search path delimiter
(``:`` on Unix, ``;`` on Windows).
.. cfunction:: 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*.
.. cfunction:: void PySys_WriteStderr(const char *format, ...)
As above, but write to :data:`sys.stderr` or *stderr* instead.
.. _processcontrol:
Process Control
===============
.. cfunction:: 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 :cfunc:`abort` is called which will attempt to produce a :file:`core`
file.
.. cfunction:: void Py_Exit(int status)
.. index::
single: Py_Finalize()
single: exit()
Exit the current process. This calls :cfunc:`Py_Finalize` and then calls the
standard C library function ``exit(status)``.
.. cfunction:: int Py_AtExit(void (*func) ())
.. index::
single: Py_Finalize()
single: cleanup functions
Register a cleanup function to be called by :cfunc:`Py_Finalize`. 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,
:cfunc:`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*.