Operating System Utilities¶
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PyObject *PyOS_FSPath(PyObject *path)¶
- Return value: New reference. Part of the Stable ABI since version 3.6.Return the file system representation for path. If the object is a strorbytesobject, then a new strong reference is returned. 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()¶
-  Part of the Stable ABI on platforms with fork() since version 3.7.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 wherefork()is defined.Warning The C fork()call should only be made from the “main” thread (of the “main” interpreter). The same is true forPyOS_BeforeFork().New in version 3.7. 
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void PyOS_AfterFork_Parent()¶
-  Part of the Stable ABI on platforms with fork() since version 3.7.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 wherefork()is defined.Warning The C fork()call should only be made from the “main” thread (of the “main” interpreter). The same is true forPyOS_AfterFork_Parent().New in version 3.7. 
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void PyOS_AfterFork_Child()¶
-  Part of the Stable ABI on platforms with fork() since version 3.7.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 wherefork()is defined.Warning The C fork()call should only be made from the “main” thread (of the “main” interpreter). The same is true forPyOS_AfterFork_Child().New in version 3.7. See also os.register_at_fork()allows registering custom Python functions to be called byPyOS_BeforeFork(),PyOS_AfterFork_Parent()andPyOS_AfterFork_Child().
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void PyOS_AfterFork()¶
-  Part of the Stable ABI on platforms with fork().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()¶
-  Part of the Stable ABI on platforms with USE_STACKCHECK since version 3.7.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 certain versions of 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)¶
-  Part of the Stable ABI.Return the current signal handler for signal i. This is a thin wrapper around either sigaction()orsignal(). 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)¶
-  Part of the Stable ABI.Set the signal handler for signal i to be h; return the old signal handler. This is a thin wrapper around either sigaction()orsignal(). 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)¶
-  Part of the Stable ABI since version 3.7.Warning This function should not be called directly: use the PyConfigAPI with thePyConfig_SetBytesString()function which ensures that Python is preinitialized.This function must not be called before Python is preinitialized and so that the LC_CTYPE locale is properly configured: see the Py_PreInitialize()function.Decode a byte string from the filesystem encoding and error handler. If the error handler is surrogateescape error handler, 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 PyMem_RawFree()to free the memory. If size is notNULL, write the number of wide characters excluding the null character into*sizeReturn NULLon decoding error or memory allocation error. If size is notNULL,*sizeis set to(size_t)-1on memory error or set to(size_t)-2on decoding error.The filesystem encoding and error handler are selected by PyConfig_Read(): seefilesystem_encodingandfilesystem_errorsmembers ofPyConfig.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()andPyUnicode_DecodeLocaleAndSize()functions.New in version 3.5. Changed in version 3.7: The function now uses the UTF-8 encoding in the Python UTF-8 Mode. Changed in version 3.8: The function now uses the UTF-8 encoding on Windows if Py_LegacyWindowsFSEncodingFlagis zero;
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char *Py_EncodeLocale(const wchar_t *text, size_t *error_pos)¶
-  Part of the Stable ABI since version 3.7.Encode a wide character string to the filesystem encoding and error handler. If the error handler is surrogateescape error handler, 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 PyMem_Free()to free the memory. ReturnNULLon 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.The filesystem encoding and error handler are selected by PyConfig_Read(): seefilesystem_encodingandfilesystem_errorsmembers ofPyConfig.Use the Py_DecodeLocale()function to decode the bytes string back to a wide character string.Warning This function must not be called before Python is preinitialized and so that the LC_CTYPE locale is properly configured: see the Py_PreInitialize()function.See also The PyUnicode_EncodeFSDefault()andPyUnicode_EncodeLocale()functions.New in version 3.5. Changed in version 3.7: The function now uses the UTF-8 encoding in the Python UTF-8 Mode. Changed in version 3.8: The function now uses the UTF-8 encoding on Windows if Py_LegacyWindowsFSEncodingFlagis zero.
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. Part of the Stable ABI.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)¶
-  Part of the Stable ABI.Set name in the sysmodule to v unless v isNULL, in which case name is deleted from the sys module. Returns0on success,-1on error.
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void PySys_ResetWarnOptions()¶
-  Part of the Stable ABI.Reset sys.warnoptionsto an empty list. This function may be called prior toPy_Initialize().
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void PySys_AddWarnOption(const wchar_t *s)¶
-  Part of the Stable ABI.This API is kept for backward compatibility: setting PyConfig.warnoptionsshould be used instead, see Python Initialization Configuration.Append s to sys.warnoptions. This function must be called prior toPy_Initialize()in order to affect the warnings filter list.Deprecated since version 3.11. 
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void PySys_AddWarnOptionUnicode(PyObject *unicode)¶
-  Part of the Stable ABI.This API is kept for backward compatibility: setting PyConfig.warnoptionsshould be used instead, see Python Initialization Configuration.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 warningsinPy_Initialize()to be effective, but can’t be called until enough of the runtime has been initialized to permit the creation of Unicode objects.Deprecated since version 3.11. 
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void PySys_SetPath(const wchar_t *path)¶
-  Part of the Stable ABI.This API is kept for backward compatibility: setting PyConfig.module_search_pathsandPyConfig.module_search_paths_setshould be used instead, see Python Initialization Configuration.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).Deprecated since version 3.11. 
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void PySys_WriteStdout(const char *format, ...)¶
-  Part of the Stable ABI.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, ...)¶
-  Part of the Stable ABI.As PySys_WriteStdout(), but write tosys.stderror stderr instead.
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void PySys_FormatStdout(const char *format, ...)¶
-  Part of the Stable ABI.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, ...)¶
-  Part of the Stable ABI.As PySys_FormatStdout(), but write tosys.stderror stderr instead.New in version 3.2. 
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void PySys_AddXOption(const wchar_t *s)¶
-  Part of the Stable ABI since version 3.7.This API is kept for backward compatibility: setting PyConfig.xoptionsshould be used instead, see Python Initialization Configuration.Parse s as a set of -Xoptions and add them to the current options mapping as returned byPySys_GetXOptions(). This function may be called prior toPy_Initialize().New in version 3.2. Deprecated since version 3.11. 
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PyObject *PySys_GetXOptions()¶
- Return value: Borrowed reference. Part of the Stable ABI since version 3.7.Return the current dictionary of -Xoptions, similarly tosys._xoptions. On error,NULLis returned and an exception is set.New in version 3.2. 
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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- Py_BuildValue()are available. If the built value is not a tuple, it will be added into a single-element tuple. (The- Nformat 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- Py_ssize_t, regardless of whether- PY_SSIZE_T_CLEANwas defined.- sys.audit()performs the same function from Python code.- New in version 3.8. - Changed in version 3.8.2: Require - Py_ssize_tfor- #format characters. Previously, an unavoidable deprecation warning was raised.
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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 - Py_Initialize(). When called after runtime initialization, existing audit hooks are notified and may silently abort the operation by raising an error subclassed from- Exception(other errors will not be silenced).- The hook function is of type int (*)(const char *event, PyObject *args, void *userData), where args is guaranteed to be a - 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 audit events table. Details are in each function’s documentation. - If the interpreter is initialized, this function raises a auditing event - sys.addaudithookwith no arguments. If any existing hooks raise an exception derived from- 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.- New in version 3.8. 
Process Control¶
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void Py_FatalError(const char *message)¶
-  Part of the Stable ABI.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 acorefile.The Py_FatalError()function is replaced with a macro which logs automatically the name of the current function, unless thePy_LIMITED_APImacro is defined.Changed in version 3.9: Log the function name automatically. 
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void Py_Exit(int status)¶
-  Part of the Stable ABI.Exit the current process. This calls Py_FinalizeEx()and then calls the standard C library functionexit(status). IfPy_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)())¶
-  Part of the Stable ABI.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()returns0; 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.