Operating System Utilities¶

PyObject*PyOS_FSPath(PyObject*path)¶

Return value: New reference. Part of theStable ABI since version 3.6.

Return the file system representation forpath. If the object is astr orbytes object, then a newstrong reference is returned.If the object implements theos.PathLike interface,then__fspath__() is returned as long as it is astr orbytes object. OtherwiseTypeError is raisedandNULL is returned.

Added in version 3.6.

intPy_FdIsInteractive(FILE*fp,constchar*filename)¶

Return true (nonzero) if the standard I/O filefp with namefilename isdeemed interactive. This is the case for files for whichisatty(fileno(fp))is true. If thePyConfig.interactive is non-zero, this functionalso returns true if thefilename pointer isNULL or if the name is equal toone of the strings'<stdin>' or'???'.

This function must not be called before Python is initialized.

voidPyOS_BeforeFork()¶

Part of theStable ABI on platforms with fork() since version 3.7.

Function to prepare some internal state before a process fork. Thisshould be called before callingfork() or any similar functionthat clones the current process.Only available on systems wherefork() is defined.

Warning

The Cfork() call should only be made from the“main” thread (of the“main” interpreter). The same istrue forPyOS_BeforeFork().

Added in version 3.7.

voidPyOS_AfterFork_Parent()¶

Part of theStable ABI on platforms with fork() since version 3.7.

Function to update some internal state after a process fork. Thisshould be called from the parent process after callingfork()or any similar function that clones the current process, regardlessof whether process cloning was successful.Only available on systems wherefork() is defined.

Warning

The Cfork() call should only be made from the“main” thread (of the“main” interpreter). The same istrue forPyOS_AfterFork_Parent().

Added in version 3.7.

voidPyOS_AfterFork_Child()¶

Part of theStable 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 callingfork(),or any similar function that clones the current process, if there isany chance the process will call back into the Python interpreter.Only available on systems wherefork() is defined.

Warning

The Cfork() call should only be made from the“main” thread (of the“main” interpreter). The same istrue forPyOS_AfterFork_Child().

Added in version 3.7.

See also

os.register_at_fork() allows registering custom Python functionsto be called byPyOS_BeforeFork(),PyOS_AfterFork_Parent() andPyOS_AfterFork_Child().

voidPyOS_AfterFork()¶

Part of theStable ABI on platforms with fork().

Function to update some internal state after a process fork; this should becalled 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 needto be called.

Deprecated since version 3.7:This function is superseded byPyOS_AfterFork_Child().

intPyOS_CheckStack()¶

Part of theStable ABI on platforms with USE_STACKCHECK since version 3.7.

Return true when the interpreter runs out of stack space. This is a reliablecheck, but is only available whenUSE_STACKCHECK is defined (currentlyon certain versions of Windows using the Microsoft Visual C++ compiler).USE_STACKCHECK will be defined automatically; you should neverchange the definition in your own code.

typedefvoid(*PyOS_sighandler_t)(int)¶

Part of theStable ABI.

PyOS_sighandler_tPyOS_getsig(inti)¶

Part of theStable ABI.

Return the current signal handler for signali. This is a thin wrapper aroundeithersigaction() orsignal(). Do not call those functionsdirectly!

PyOS_sighandler_tPyOS_setsig(inti,PyOS_sighandler_th)¶

Part of theStable ABI.

Set the signal handler for signali to beh; return the old signal handler.This is a thin wrapper around eithersigaction() orsignal(). Donot call those functions directly!

wchar_t*Py_DecodeLocale(constchar*arg,size_t*size)¶

Part of theStable ABI since version 3.7.

Warning

This function should not be called directly: use thePyConfigAPI with thePyConfig_SetBytesString() function which ensuresthatPython is preinitialized.

This function must not be called beforePython is preinitialized and so that the LC_CTYPE locale is properly configured: seethePy_PreInitialize() function.

Decode a byte string from thefilesystem encoding and error handler.If the error handler issurrogateescape error handler, undecodable bytes are decoded as characters in rangeU+DC80..U+DCFF; and if a byte sequence can be decoded as a surrogatecharacter, the bytes are escaped using the surrogateescape error handlerinstead of decoding them.

Return a pointer to a newly allocated wide character string, usePyMem_RawFree() to free the memory. If size is notNULL, writethe number of wide characters excluding the null character into*size

ReturnNULL on decoding error or memory allocation error. Ifsize isnotNULL,*size is set to(size_t)-1 on memory error or set to(size_t)-2 on decoding error.

Thefilesystem encoding and error handler are selected byPyConfig_Read(): seefilesystem_encoding andfilesystem_errors members ofPyConfig.

Decoding errors should never happen, unless there is a bug in the Clibrary.

Use thePy_EncodeLocale() function to encode the character stringback to a byte string.

See also

ThePyUnicode_DecodeFSDefaultAndSize() andPyUnicode_DecodeLocaleAndSize() functions.

Added in version 3.5.

Changed in version 3.7:The function now uses the UTF-8 encoding in thePython UTF-8 Mode.

Changed in version 3.8:The function now uses the UTF-8 encoding on Windows ifPyPreConfig.legacy_windows_fs_encoding is zero;

char*Py_EncodeLocale(constwchar_t*text,size_t*error_pos)¶

Part of theStable ABI since version 3.7.

Encode a wide character string to thefilesystem encoding and errorhandler. If the error handler issurrogateescape error handler, surrogate characters in the range U+DC80..U+DCFF areconverted to bytes 0x80..0xFF.

Return a pointer to a newly allocated byte string, usePyMem_Free()to free the memory. ReturnNULL on encoding error or memory allocationerror.

If error_pos is notNULL,*error_pos is set to(size_t)-1 onsuccess, or set to the index of the invalid character on encoding error.

Thefilesystem encoding and error handler are selected byPyConfig_Read(): seefilesystem_encoding andfilesystem_errors members ofPyConfig.

Use thePy_DecodeLocale() function to decode the bytes string backto a wide character string.

Warning

This function must not be called beforePython is preinitialized and so that the LC_CTYPE locale is properly configured: seethePy_PreInitialize() function.

See also

ThePyUnicode_EncodeFSDefault() andPyUnicode_EncodeLocale() functions.

Added in version 3.5.

Changed in version 3.7:The function now uses the UTF-8 encoding in thePython UTF-8 Mode.

Changed in version 3.8:The function now uses the UTF-8 encoding on Windows ifPyPreConfig.legacy_windows_fs_encoding is zero.

System Functions¶

These are utility functions that make functionality from thesys moduleaccessible to C code. They all work with the current interpreter thread’ssys module’s dict, which is contained in the internal thread state structure.

PyObject*PySys_GetObject(constchar*name)¶

Return value: Borrowed reference. Part of theStable ABI.

Return the objectname from thesys module orNULL if it doesnot exist, without setting an exception.

intPySys_SetObject(constchar*name,PyObject*v)¶

Part of theStable ABI.

Setname in thesys module tov unlessv isNULL, in whichcasename is deleted from the sys module. Returns0 on success,-1on error.

voidPySys_ResetWarnOptions()¶

Part of theStable ABI.

Resetsys.warnoptions to an empty list. This function may becalled prior toPy_Initialize().

Deprecated since version 3.13, will be removed in version 3.15:Clearsys.warnoptions andwarnings.filters instead.

voidPySys_WriteStdout(constchar*format,...)¶

Part of theStable ABI.

Write the output string described byformat tosys.stdout. Noexceptions are raised, even if truncation occurs (see below).

format should limit the total size of the formatted output string to1000 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 numbercalculated so that <N> plus the maximum size of other formatted text does notexceed 1000 bytes. Also watch out for “%f”, which can print hundreds ofdigits for very large numbers.

If a problem occurs, orsys.stdout is unset, the formatted messageis written to the real (C level)stdout.

voidPySys_WriteStderr(constchar*format,...)¶

Part of theStable ABI.

AsPySys_WriteStdout(), but write tosys.stderr orstderrinstead.

voidPySys_FormatStdout(constchar*format,...)¶

Part of theStable ABI.

Function similar to PySys_WriteStdout() but format the message usingPyUnicode_FromFormatV() and don’t truncate the message to anarbitrary length.

Added in version 3.2.

voidPySys_FormatStderr(constchar*format,...)¶

Part of theStable ABI.

AsPySys_FormatStdout(), but write tosys.stderr orstderrinstead.

Added in version 3.2.

PyObject*PySys_GetXOptions()¶

Return value: Borrowed reference. Part of theStable ABI since version 3.7.

Return the current dictionary of-X options, similarly tosys._xoptions. On error,NULL is returned and an exception isset.

Added in version 3.2.

intPySys_Audit(constchar*event,constchar*format,...)¶

Part of theStable ABI since version 3.13.

Raise an auditing event with any active hooks. Return zero for successand non-zero with an exception set on failure.

Theevent string argument must not beNULL.

If any hooks have been added,format and other arguments will be usedto construct a tuple to pass. Apart fromN, the same format charactersas used inPy_BuildValue() are available. If the built value is nota tuple, it will be added into a single-element tuple.

TheN format option must not be used. It consumes a reference, but sincethere 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 asPy_ssize_t, regardless of whetherPY_SSIZE_T_CLEAN was defined.

sys.audit() performs the same function from Python code.

See alsoPySys_AuditTuple().

Added in version 3.8.

Changed in version 3.8.2:RequirePy_ssize_t for# format characters. Previously, anunavoidable deprecation warning was raised.

intPySys_AuditTuple(constchar*event,PyObject*args)¶

Part of theStable ABI since version 3.13.

Similar toPySys_Audit(), but pass arguments as a Python object.args must be atuple. To pass no arguments,args can beNULL.

Added in version 3.13.

intPySys_AddAuditHook(Py_AuditHookFunctionhook,void*userData)¶

Append the callablehook to the list of active auditing hooks.Return zero on successand non-zero on failure. If the runtime has been initialized, also set anerror on failure. Hooks added through this API are called for allinterpreters created by the runtime.

TheuserData pointer is passed into the hook function. Since hookfunctions may be called from different runtimes, this pointer should notrefer directly to Python state.

This function is safe to call beforePy_Initialize(). When calledafter runtime initialization, existing audit hooks are notified and maysilently abort the operation by raising an error subclassed fromException (other errors will not be silenced).

The hook function is always called with the GIL held by the Pythoninterpreter that raised the event.

SeePEP 578 for a detailed description of auditing. Functions in theruntime and standard library that raise events are listed in theaudit events table.Details are in each function’s documentation.

If the interpreter is initialized, this function raises an auditing eventsys.addaudithook with no arguments. If any existing hooks raise anexception derived fromException, the new hook will not beadded and the exception is cleared. As a result, callers cannot assumethat their hook has been added unless they control all existing hooks.

typedefint(*Py_AuditHookFunction)(constchar*event,PyObject*args,void*userData)¶

The type of the hook function.event is the C string event argument passed toPySys_Audit() orPySys_AuditTuple().args is guaranteed to be aPyTupleObject.userData is the argument passed to PySys_AddAuditHook().

Added in version 3.8.

Process Control¶

voidPy_FatalError(constchar*message)¶

Part of theStable 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 wouldmake it dangerous to continue using the Python interpreter; e.g., when theobject administration appears to be corrupted. On Unix, the standard C libraryfunctionabort() is called which will attempt to produce acorefile.

ThePy_FatalError() function is replaced with a macro which logsautomatically the name of the current function, unless thePy_LIMITED_API macro is defined.

Changed in version 3.9:Log the function name automatically.

voidPy_Exit(intstatus)¶

Part of theStable ABI.

Exit the current process. This callsPy_FinalizeEx() and then calls thestandard 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.

intPy_AtExit(void(*func)())¶

Part of theStable ABI.

Register a cleanup function to be called byPy_FinalizeEx(). The cleanupfunction will be called with no arguments and should return no value. At most32 cleanup functions can be registered. When the registration is successful,Py_AtExit() returns0; on failure, it returns-1. The cleanupfunction registered last is called first. Each cleanup function will be calledat most once. Since Python’s internal finalization will have completed beforethe cleanup function, no Python APIs should be called byfunc.

See also

PyUnstable_AtExit() for passing avoid*data argument.