Operating System Utilities
**************************

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 "str" or "bytes" object, then a new *strong reference* is
   returned. If the object implements the "os.PathLike" interface,
   then "__fspath__()" is returned as long as it is a "str" or "bytes"
   object. Otherwise "TypeError" is raised and "NULL" is returned.

   Added in version 3.6.

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 "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.

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
   where "fork()" is defined.

   Warning:

     The C "fork()" call should only be made from the "main" thread
     (of the "main" interpreter).  The same is true for
     "PyOS_BeforeFork()".

   Added in version 3.7.

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
   where "fork()" is defined.

   Warning:

     The C "fork()" call should only be made from the "main" thread
     (of the "main" interpreter).  The same is true for
     "PyOS_AfterFork_Parent()".

   Added in version 3.7.

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 where "fork()" is defined.

   Warning:

     The C "fork()" call should only be made from the "main" thread
     (of the "main" interpreter).  The same is true for
     "PyOS_AfterFork_Child()".

   Added 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()".

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()".

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_STACKCHECK" is
   defined (currently on certain versions of Windows using the
   Microsoft Visual C++ compiler). "USE_STACKCHECK" will be defined
   automatically; you should never change the definition in your own
   code.

typedef void (*PyOS_sighandler_t)(int)
    * Part of the Stable ABI.*

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()" or "signal()".  Do not call
   those functions directly!

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()"
   or "signal()".  Do not call those functions directly!

int PyOS_InterruptOccurred(void)
    * Part of the Stable ABI.*

   Check if a "SIGINT" signal has been received.

   Returns "1" if a "SIGINT" has occurred and clears the signal flag,
   or "0" otherwise.

   In most cases, you should prefer "PyErr_CheckSignals()" over this
   function. "PyErr_CheckSignals()" invokes the appropriate signal
   handlers for all pending signals, allowing Python code to handle
   the signal properly. This function only detects "SIGINT" and does
   not invoke any Python signal handlers.

   This function is async-signal-safe and this function cannot fail.
   The caller must hold an *attached thread state*.

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 "PyConfig"
     API with the "PyConfig_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 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 *filesystem encoding and error handler* are selected by
   "PyConfig_Read()": see "filesystem_encoding" and
   "filesystem_errors" members of "PyConfig".

   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.

   Added 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 "PyPreConfig.legacy_windows_fs_encoding" is zero;

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. 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 *filesystem encoding and error handler* are selected by
   "PyConfig_Read()": see "filesystem_encoding" and
   "filesystem_errors" members of "PyConfig".

   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()" and "PyUnicode_EncodeLocale()"
     functions.

   Added 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 "PyPreConfig.legacy_windows_fs_encoding" is zero.

FILE *Py_fopen(PyObject *path, const char *mode)

   Similar to "fopen()", but *path* is a Python object and an
   exception is set on error.

   *path* must be a "str" object, a "bytes" object, or a *path-like
   object*.

   On success, return the new file pointer. On error, set an exception
   and return "NULL".

   The file must be closed by "Py_fclose()" rather than calling
   directly "fclose()".

   The file descriptor is created non-inheritable (**PEP 446**).

   The caller must have an *attached thread state*.

   Added in version 3.14.

int Py_fclose(FILE *file)

   Close a file that was opened by "Py_fopen()".

   On success, return "0". On error, return "EOF" and "errno" is set
   to indicate the error. In either case, any further access
   (including another call to "Py_fclose()") to the stream results in
   undefined behavior.

   Added in version 3.14.


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.

PyObject *PySys_GetObject(const char *name)
    *Return value: Borrowed reference.** Part of the Stable ABI.*

   Return the object *name* from the "sys" module or "NULL" if it does
   not exist, without setting an exception.

int PySys_SetObject(const char *name, PyObject *v)
    * Part of the Stable ABI.*

   Set *name* in the "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.

void PySys_ResetWarnOptions()
    * Part of the Stable ABI.*

   Reset "sys.warnoptions" to an empty list. This function may be
   called prior to "Py_Initialize()".

   Deprecated since version 3.13, will be removed in version 3.15:
   Clear "sys.warnoptions" and "warnings.filters" instead.

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.stdout" is unset, the formatted
   message is written to the real (C level) *stdout*.

void PySys_WriteStderr(const char *format, ...)
    * Part of the Stable ABI.*

   As "PySys_WriteStdout()", but write to "sys.stderr" or *stderr*
   instead.

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.

   Added in version 3.2.

void PySys_FormatStderr(const char *format, ...)
    * Part of the Stable ABI.*

   As "PySys_FormatStdout()", but write to "sys.stderr" or *stderr*
   instead.

   Added in version 3.2.

PyObject *PySys_GetXOptions()
    *Return value: Borrowed reference.** Part of the Stable ABI since
   version 3.7.*

   Return the current dictionary of "-X" options, similarly to
   "sys._xoptions".  On error, "NULL" is returned and an exception is
   set.

   Added in version 3.2.

int PySys_Audit(const char *event, const char *format, ...)
    * Part of the Stable ABI since version 3.13.*

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

   The *event* string argument must not be *NULL*.

   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 "N" format option must not be used. It 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_CLEAN" was defined.

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

   See also "PySys_AuditTuple()".

   Added in version 3.8.

   Changed in version 3.8.2: Require "Py_ssize_t" for "#" format
   characters. Previously, an unavoidable deprecation warning was
   raised.

int PySys_AuditTuple(const char *event, PyObject *args)
    * Part of the Stable ABI since version 3.13.*

   Similar to "PySys_Audit()", but pass arguments as a Python object.
   *args* must be a "tuple". To pass no arguments, *args* can be
   *NULL*.

   Added in version 3.13.

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 always called with an *attached thread state*
   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 an auditing
   event "sys.addaudithook" with 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.

   typedef int (*Py_AuditHookFunction)(const char *event, PyObject *args, void *userData)

      The type of the hook function. *event* is the C string event
      argument passed to "PySys_Audit()" or "PySys_AuditTuple()".
      *args* is guaranteed to be a "PyTupleObject". *userData* is the
      argument passed to PySys_AddAuditHook().

   Added in version 3.8.


Process Control
***************

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 a "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.

   Changed in version 3.9: Log the function name automatically.

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 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.

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()" 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*.

   See also:

     "PyUnstable_AtExit()" for passing a "void *data" argument.
