Operating System Utilities¶
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PyObject* PyOS_FSPath(PyObject *path)¶
- Return value: New reference.Return the file system representation for path. If the object is a strorbytesobject, then its reference count is incremented. If the object implements theos.PathLikeinterface, then__fspath__()is returned as long as it is astrorbytesobject. OtherwiseTypeErroris raised andNULLis returned.New in version 3.6. 
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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- Py_InteractiveFlagis true, this function also returns true if the filename pointer is- NULLor if the name is equal to one of the strings- '<stdin>'or- '???'.
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void PyOS_BeforeFork()¶
- Function to prepare some internal state before a process fork. This should be called before calling - fork()or any similar function that clones the current process. Only available on systems where- fork()is defined.- New in version 3.7. 
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void PyOS_AfterFork_Parent()¶
- Function to update some internal state after a process fork. This should be called from the parent process after calling - fork()or any similar function that clones the current process, regardless of whether process cloning was successful. Only available on systems where- fork()is defined.- New in version 3.7. 
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void PyOS_AfterFork_Child()¶
- Function to update internal interpreter state after a process fork. This must be called from the child process after calling - 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- fork()is defined.- New in version 3.7. - See also - os.register_at_fork()allows registering custom Python functions to be called by- PyOS_BeforeFork(),- PyOS_AfterFork_Parent()and- PyOS_AfterFork_Child().
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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 since version 3.7: This function is superseded by - PyOS_AfterFork_Child().
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int PyOS_CheckStack()¶
- Return true when the interpreter runs out of stack space. This is a reliable check, but is only available when - USE_STACKCHECKis defined (currently on Windows using the Microsoft Visual C++ compiler).- USE_STACKCHECKwill be defined automatically; you should never change the definition in your own code.
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PyOS_sighandler_t PyOS_getsig(int i)¶
- Return the current signal handler for signal i. This is a thin wrapper around either - sigaction()or- signal(). Do not call those functions directly!- PyOS_sighandler_tis a typedef alias for- void (*)(int).
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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 - sigaction()or- signal(). Do not call those functions directly!- PyOS_sighandler_tis a typedef alias for- void (*)(int).
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wchar_t* Py_DecodeLocale(const char* arg, size_t *size)¶
- Decode a byte string from the locale encoding with the surrogateescape error handler: undecodable bytes are decoded as characters in range U+DC80..U+DCFF. If a byte sequence can be decoded as a surrogate character, escape the bytes using the surrogateescape error handler instead of decoding them. - Encoding, highest priority to lowest priority: - UTF-8on macOS and Android;
- UTF-8if the Python UTF-8 mode is enabled;
- ASCIIif the- LC_CTYPElocale is- "C",- nl_langinfo(CODESET)returns the- ASCIIencoding (or an alias), and- mbstowcs()and- wcstombs()functions uses the- ISO-8859-1encoding.
- the current locale encoding. 
 - Return a pointer to a newly allocated wide character string, use - PyMem_RawFree()to free the memory. If size is not- NULL, write the number of wide characters excluding the null character into- *size- Return - NULLon decoding error or memory allocation error. If size is not- NULL,- *sizeis set to- (size_t)-1on memory error or set to- (size_t)-2on decoding error.- Decoding errors should never happen, unless there is a bug in the C library. - Use the - Py_EncodeLocale()function to encode the character string back to a byte string.- See also - The - PyUnicode_DecodeFSDefaultAndSize()and- PyUnicode_DecodeLocaleAndSize()functions.- New in version 3.5. - Changed in version 3.7: The function now uses the UTF-8 encoding in the UTF-8 mode. 
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char* Py_EncodeLocale(const wchar_t *text, size_t *error_pos)¶
- Encode a wide character string to the locale encoding with the surrogateescape error handler: surrogate characters in the range U+DC80..U+DCFF are converted to bytes 0x80..0xFF. - Encoding, highest priority to lowest priority: - UTF-8on macOS and Android;
- UTF-8if the Python UTF-8 mode is enabled;
- ASCIIif the- LC_CTYPElocale is- "C",- nl_langinfo(CODESET)returns the- ASCIIencoding (or an alias), and- mbstowcs()and- wcstombs()functions uses the- ISO-8859-1encoding.
- the current locale encoding. 
 - The function uses the UTF-8 encoding in the Python UTF-8 mode. - Return a pointer to a newly allocated byte string, use - PyMem_Free()to free the memory. Return- NULLon encoding error or memory allocation error- If error_pos is not - NULL,- *error_posis set to- (size_t)-1on success, or set to the index of the invalid character on encoding error.- Use the - Py_DecodeLocale()function to decode the bytes string back to a wide character string.- Changed in version 3.7: The function now uses the UTF-8 encoding in the UTF-8 mode. - See also - The - PyUnicode_EncodeFSDefault()and- PyUnicode_EncodeLocale()functions.- New in version 3.5. - Changed in version 3.7: The function now supports the UTF-8 mode. 
System Functions¶
These are utility functions that make functionality from the sys module
accessible to C code.  They all work with the current interpreter thread’s
sys module’s dict, which is contained in the internal thread state structure.
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PyObject *PySys_GetObject(const char *name)¶
- Return value: Borrowed reference.Return the object name from the sysmodule orNULLif it does not exist, without setting an exception.
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int PySys_SetObject(const char *name, PyObject *v)¶
- Set name in the - sysmodule to v unless v is- NULL, in which case name is deleted from the sys module. Returns- 0on success,- -1on error.
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void PySys_ResetWarnOptions()¶
- Reset - sys.warnoptionsto an empty list. This function may be called prior to- Py_Initialize().
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void PySys_AddWarnOption(const wchar_t *s)¶
- Append s to - sys.warnoptions. This function must be called prior to- Py_Initialize()in order to affect the warnings filter list.
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void PySys_AddWarnOptionUnicode(PyObject *unicode)¶
- Append unicode to - sys.warnoptions.- Note: this function is not currently usable from outside the CPython implementation, as it must be called prior to the implicit import of - warningsin- Py_Initialize()to be effective, but can’t be called until enough of the runtime has been initialized to permit the creation of Unicode objects.
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void PySys_SetPath(const wchar_t *path)¶
- Set - sys.pathto 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).
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void PySys_WriteStdout(const char *format, ...)¶
- Write the output string described by format to - 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 - sys.stdoutis unset, the formatted message is written to the real (C level) stdout.
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void PySys_WriteStderr(const char *format, ...)¶
- As - PySys_WriteStdout(), but write to- sys.stderror stderr instead.
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void PySys_FormatStdout(const char *format, ...)¶
- Function similar to PySys_WriteStdout() but format the message using - PyUnicode_FromFormatV()and don’t truncate the message to an arbitrary length.- New in version 3.2. 
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void PySys_FormatStderr(const char *format, ...)¶
- As - PySys_FormatStdout(), but write to- sys.stderror stderr instead.- New in version 3.2. 
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void PySys_AddXOption(const wchar_t *s)¶
- Parse s as a set of - -Xoptions and add them to the current options mapping as returned by- PySys_GetXOptions(). This function may be called prior to- Py_Initialize().- New in version 3.2. 
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PyObject *PySys_GetXOptions()¶
- Return value: Borrowed reference.Return the current dictionary of -Xoptions, similarly tosys._xoptions. On error,NULLis returned and an exception is set.New in version 3.2. 
Process Control¶
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void Py_FatalError(const char *message)¶
- 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 - abort()is called which will attempt to produce a- corefile.
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void Py_Exit(int status)¶
- Exit the current process. This calls - Py_FinalizeEx()and then calls the standard C library function- exit(status). If- Py_FinalizeEx()indicates an error, the exit status is set to 120.- Changed in version 3.6: Errors from finalization no longer ignored. 
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int Py_AtExit(void (*func)())¶
- Register a cleanup function to be called by - 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,- 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.
