Exception Handling
******************

The functions described in this chapter will let you handle and raise
Python exceptions.  It is important to understand some of the basics
of Python exception handling.  It works somewhat like the POSIX
"errno" variable: there is a global indicator (per thread) of the last
error that occurred.  Most C API functions don't clear this on
success, but will set it to indicate the cause of the error on
failure.  Most C API functions also return an error indicator, usually
"NULL" if they are supposed to return a pointer, or "-1" if they
return an integer (exception: the "PyArg_*" functions return "1" for
success and "0" for failure).

Concretely, the error indicator consists of three object pointers: the
exception's type, the exception's value, and the traceback object.
Any of those pointers can be "NULL" if non-set (although some
combinations are forbidden, for example you can't have a non-"NULL"
traceback if the exception type is "NULL").

When a function must fail because some function it called failed, it
generally doesn't set the error indicator; the function it called
already set it.  It is responsible for either handling the error and
clearing the exception or returning after cleaning up any resources it
holds (such as object references or memory allocations); it should
*not* continue normally if it is not prepared to handle the error.  If
returning due to an error, it is important to indicate to the caller
that an error has been set.  If the error is not handled or carefully
propagated, additional calls into the Python/C API may not behave as
intended and may fail in mysterious ways.

Note:

  The error indicator is **not** the result of "sys.exc_info()". The
  former corresponds to an exception that is not yet caught (and is
  therefore still propagating), while the latter returns an exception
  after it is caught (and has therefore stopped propagating).


Printing and clearing
=====================

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

   Clear the error indicator.  If the error indicator is not set,
   there is no effect.

void PyErr_PrintEx(int set_sys_last_vars)
    * Part of the Stable ABI.*

   Print a standard traceback to "sys.stderr" and clear the error
   indicator. **Unless** the error is a "SystemExit", in that case no
   traceback is printed and the Python process will exit with the
   error code specified by the "SystemExit" instance.

   Call this function **only** when the error indicator is set.
   Otherwise it will cause a fatal error!

   If *set_sys_last_vars* is nonzero, the variable "sys.last_exc" is
   set to the printed exception. For backwards compatibility, the
   deprecated variables "sys.last_type", "sys.last_value" and
   "sys.last_traceback" are also set to the type, value and traceback
   of this exception, respectively.

   Changed in version 3.12: The setting of "sys.last_exc" was added.

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

   Alias for "PyErr_PrintEx(1)".

void PyErr_WriteUnraisable(PyObject *obj)
    * Part of the Stable ABI.*

   Call "sys.unraisablehook()" using the current exception and *obj*
   argument.

   This utility function prints a warning message to "sys.stderr" when
   an exception has been set but it is impossible for the interpreter
   to actually raise the exception.  It is used, for example, when an
   exception occurs in an "__del__()" method.

   The function is called with a single argument *obj* that identifies
   the context in which the unraisable exception occurred. If
   possible, the repr of *obj* will be printed in the warning message.
   If *obj* is "NULL", only the traceback is printed.

   An exception must be set when calling this function.

   Changed in version 3.4: Print a traceback. Print only traceback if
   *obj* is "NULL".

   Changed in version 3.8: Use "sys.unraisablehook()".

void PyErr_FormatUnraisable(const char *format, ...)

   Similar to "PyErr_WriteUnraisable()", but the *format* and
   subsequent parameters help format the warning message; they have
   the same meaning and values as in "PyUnicode_FromFormat()".
   "PyErr_WriteUnraisable(obj)" is roughly equivalent to
   "PyErr_FormatUnraisable("Exception ignored in: %R", obj)". If
   *format* is "NULL", only the traceback is printed.

   Added in version 3.13.

void PyErr_DisplayException(PyObject *exc)
    * Part of the Stable ABI since version 3.12.*

   Print the standard traceback display of "exc" to "sys.stderr",
   including chained exceptions and notes.

   Added in version 3.12.


Raising exceptions
==================

These functions help you set the current thread's error indicator. For
convenience, some of these functions will always return a "NULL"
pointer for use in a "return" statement.

void PyErr_SetString(PyObject *type, const char *message)
    * Part of the Stable ABI.*

   This is the most common way to set the error indicator.  The first
   argument specifies the exception type; it is normally one of the
   standard exceptions, e.g. "PyExc_RuntimeError".  You need not
   create a new *strong reference* to it (e.g. with "Py_INCREF()").
   The second argument is an error message; it is decoded from
   "'utf-8'".

void PyErr_SetObject(PyObject *type, PyObject *value)
    * Part of the Stable ABI.*

   This function is similar to "PyErr_SetString()" but lets you
   specify an arbitrary Python object for the "value" of the
   exception.

PyObject *PyErr_Format(PyObject *exception, const char *format, ...)
    *Return value: Always NULL.** Part of the Stable ABI.*

   This function sets the error indicator and returns "NULL".
   *exception* should be a Python exception class.  The *format* and
   subsequent parameters help format the error message; they have the
   same meaning and values as in "PyUnicode_FromFormat()". *format* is
   an ASCII-encoded string.

PyObject *PyErr_FormatV(PyObject *exception, const char *format, va_list vargs)
    *Return value: Always NULL.** Part of the Stable ABI since version
   3.5.*

   Same as "PyErr_Format()", but taking a "va_list" argument rather
   than a variable number of arguments.

   Added in version 3.5.

void PyErr_SetNone(PyObject *type)
    * Part of the Stable ABI.*

   This is a shorthand for "PyErr_SetObject(type, Py_None)".

int PyErr_BadArgument()
    * Part of the Stable ABI.*

   This is a shorthand for "PyErr_SetString(PyExc_TypeError,
   message)", where *message* indicates that a built-in operation was
   invoked with an illegal argument.  It is mostly for internal use.

PyObject *PyErr_NoMemory()
    *Return value: Always NULL.** Part of the Stable ABI.*

   This is a shorthand for "PyErr_SetNone(PyExc_MemoryError)"; it
   returns "NULL" so an object allocation function can write "return
   PyErr_NoMemory();" when it runs out of memory.

PyObject *PyErr_SetFromErrno(PyObject *type)
    *Return value: Always NULL.** Part of the Stable ABI.*

   This is a convenience function to raise an exception when a C
   library function has returned an error and set the C variable
   "errno".  It constructs a tuple object whose first item is the
   integer "errno" value and whose second item is the corresponding
   error message (gotten from "strerror()"), and then calls
   "PyErr_SetObject(type, object)".  On Unix, when the "errno" value
   is "EINTR", indicating an interrupted system call, this calls
   "PyErr_CheckSignals()", and if that set the error indicator, leaves
   it set to that.  The function always returns "NULL", so a wrapper
   function around a system call can write "return
   PyErr_SetFromErrno(type);" when the system call returns an error.

PyObject *PyErr_SetFromErrnoWithFilenameObject(PyObject *type, PyObject *filenameObject)
    *Return value: Always NULL.** Part of the Stable ABI.*

   Similar to "PyErr_SetFromErrno()", with the additional behavior
   that if *filenameObject* is not "NULL", it is passed to the
   constructor of *type* as a third parameter.  In the case of
   "OSError" exception, this is used to define the "filename"
   attribute of the exception instance.

PyObject *PyErr_SetFromErrnoWithFilenameObjects(PyObject *type, PyObject *filenameObject, PyObject *filenameObject2)
    *Return value: Always NULL.** Part of the Stable ABI since version
   3.7.*

   Similar to "PyErr_SetFromErrnoWithFilenameObject()", but takes a
   second filename object, for raising errors when a function that
   takes two filenames fails.

   Added in version 3.4.

PyObject *PyErr_SetFromErrnoWithFilename(PyObject *type, const char *filename)
    *Return value: Always NULL.** Part of the Stable ABI.*

   Similar to "PyErr_SetFromErrnoWithFilenameObject()", but the
   filename is given as a C string.  *filename* is decoded from the
   *filesystem encoding and error handler*.

PyObject *PyErr_SetFromWindowsErr(int ierr)
    *Return value: Always NULL.** Part of the Stable ABI on Windows
   since version 3.7.*

   This is a convenience function to raise "OSError". If called with
   *ierr* of "0", the error code returned by a call to
   "GetLastError()" is used instead.  It calls the Win32 function
   "FormatMessage()" to retrieve the Windows description of error code
   given by *ierr* or "GetLastError()", then it constructs a "OSError"
   object with the "winerror" attribute set to the error code, the
   "strerror" attribute set to the corresponding error message (gotten
   from "FormatMessage()"), and then calls
   "PyErr_SetObject(PyExc_OSError, object)". This function always
   returns "NULL".

   Availability: Windows.

PyObject *PyErr_SetExcFromWindowsErr(PyObject *type, int ierr)
    *Return value: Always NULL.** Part of the Stable ABI on Windows
   since version 3.7.*

   Similar to "PyErr_SetFromWindowsErr()", with an additional
   parameter specifying the exception type to be raised.

   Availability: Windows.

PyObject *PyErr_SetFromWindowsErrWithFilename(int ierr, const char *filename)
    *Return value: Always NULL.** Part of the Stable ABI on Windows
   since version 3.7.*

   Similar to "PyErr_SetFromWindowsErr()", with the additional
   behavior that if *filename* is not "NULL", it is decoded from the
   filesystem encoding ("os.fsdecode()") and passed to the constructor
   of "OSError" as a third parameter to be used to define the
   "filename" attribute of the exception instance.

   Availability: Windows.

PyObject *PyErr_SetExcFromWindowsErrWithFilenameObject(PyObject *type, int ierr, PyObject *filename)
    *Return value: Always NULL.** Part of the Stable ABI on Windows
   since version 3.7.*

   Similar to "PyErr_SetExcFromWindowsErr()", with the additional
   behavior that if *filename* is not "NULL", it is passed to the
   constructor of "OSError" as a third parameter to be used to define
   the "filename" attribute of the exception instance.

   Availability: Windows.

PyObject *PyErr_SetExcFromWindowsErrWithFilenameObjects(PyObject *type, int ierr, PyObject *filename, PyObject *filename2)
    *Return value: Always NULL.** Part of the Stable ABI on Windows
   since version 3.7.*

   Similar to "PyErr_SetExcFromWindowsErrWithFilenameObject()", but
   accepts a second filename object.

   Availability: Windows.

   Added in version 3.4.

PyObject *PyErr_SetExcFromWindowsErrWithFilename(PyObject *type, int ierr, const char *filename)
    *Return value: Always NULL.** Part of the Stable ABI on Windows
   since version 3.7.*

   Similar to "PyErr_SetFromWindowsErrWithFilename()", with an
   additional parameter specifying the exception type to be raised.

   Availability: Windows.

PyObject *PyErr_SetImportError(PyObject *msg, PyObject *name, PyObject *path)
    *Return value: Always NULL.** Part of the Stable ABI since version
   3.7.*

   This is a convenience function to raise "ImportError". *msg* will
   be set as the exception's message string. *name* and *path*, both
   of which can be "NULL", will be set as the "ImportError"'s
   respective "name" and "path" attributes.

   Added in version 3.3.

PyObject *PyErr_SetImportErrorSubclass(PyObject *exception, PyObject *msg, PyObject *name, PyObject *path)
    *Return value: Always NULL.** Part of the Stable ABI since version
   3.6.*

   Much like "PyErr_SetImportError()" but this function allows for
   specifying a subclass of "ImportError" to raise.

   Added in version 3.6.

void PyErr_SyntaxLocationObject(PyObject *filename, int lineno, int col_offset)

   Set file, line, and offset information for the current exception.
   If the current exception is not a "SyntaxError", then it sets
   additional attributes, which make the exception printing subsystem
   think the exception is a "SyntaxError".

   Added in version 3.4.

void PyErr_RangedSyntaxLocationObject(PyObject *filename, int lineno, int col_offset, int end_lineno, int end_col_offset)

   Similar to "PyErr_SyntaxLocationObject()", but also sets the
   *end_lineno* and *end_col_offset* information for the current
   exception.

   Added in version 3.10.

void PyErr_SyntaxLocationEx(const char *filename, int lineno, int col_offset)
    * Part of the Stable ABI since version 3.7.*

   Like "PyErr_SyntaxLocationObject()", but *filename* is a byte
   string decoded from the *filesystem encoding and error handler*.

   Added in version 3.2.

void PyErr_SyntaxLocation(const char *filename, int lineno)
    * Part of the Stable ABI.*

   Like "PyErr_SyntaxLocationEx()", but the *col_offset* parameter is
   omitted.

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

   This is a shorthand for "PyErr_SetString(PyExc_SystemError,
   message)", where *message* indicates that an internal operation
   (e.g. a Python/C API function) was invoked with an illegal
   argument.  It is mostly for internal use.

PyObject *PyErr_ProgramTextObject(PyObject *filename, int lineno)

   Get the source line in *filename* at line *lineno*. *filename*
   should be a Python "str" object.

   On success, this function returns a Python string object with the
   found line. On failure, this function returns "NULL" without an
   exception set.

PyObject *PyErr_ProgramText(const char *filename, int lineno)
    * Part of the Stable ABI.*

   Similar to "PyErr_ProgramTextObject()", but *filename* is a const
   char*, which is decoded with the *filesystem encoding and error
   handler*, instead of a Python object reference.


Issuing warnings
================

Use these functions to issue warnings from C code.  They mirror
similar functions exported by the Python "warnings" module.  They
normally print a warning message to *sys.stderr*; however, it is also
possible that the user has specified that warnings are to be turned
into errors, and in that case they will raise an exception.  It is
also possible that the functions raise an exception because of a
problem with the warning machinery. The return value is "0" if no
exception is raised, or "-1" if an exception is raised.  (It is not
possible to determine whether a warning message is actually printed,
nor what the reason is for the exception; this is intentional.)  If an
exception is raised, the caller should do its normal exception
handling (for example, "Py_DECREF()" owned references and return an
error value).

int PyErr_WarnEx(PyObject *category, const char *message, Py_ssize_t stack_level)
    * Part of the Stable ABI.*

   Issue a warning message.  The *category* argument is a warning
   category (see below) or "NULL"; the *message* argument is a UTF-8
   encoded string.  *stack_level* is a positive number giving a number
   of stack frames; the warning will be issued from the  currently
   executing line of code in that stack frame.  A *stack_level* of 1
   is the function calling "PyErr_WarnEx()", 2 is  the function above
   that, and so forth.

   Warning categories must be subclasses of "PyExc_Warning";
   "PyExc_Warning" is a subclass of "PyExc_Exception"; the default
   warning category is "PyExc_RuntimeWarning". The standard Python
   warning categories are available as global variables whose names
   are enumerated at Warning types.

   For information about warning control, see the documentation for
   the "warnings" module and the "-W" option in the command line
   documentation.  There is no C API for warning control.

int PyErr_WarnExplicitObject(PyObject *category, PyObject *message, PyObject *filename, int lineno, PyObject *module, PyObject *registry)

   Issue a warning message with explicit control over all warning
   attributes.  This is a straightforward wrapper around the Python
   function "warnings.warn_explicit()"; see there for more
   information.  The *module* and *registry* arguments may be set to
   "NULL" to get the default effect described there.

   Added in version 3.4.

int PyErr_WarnExplicit(PyObject *category, const char *message, const char *filename, int lineno, const char *module, PyObject *registry)
    * Part of the Stable ABI.*

   Similar to "PyErr_WarnExplicitObject()" except that *message* and
   *module* are UTF-8 encoded strings, and *filename* is decoded from
   the *filesystem encoding and error handler*.

int PyErr_WarnFormat(PyObject *category, Py_ssize_t stack_level, const char *format, ...)
    * Part of the Stable ABI.*

   Function similar to "PyErr_WarnEx()", but use
   "PyUnicode_FromFormat()" to format the warning message.  *format*
   is an ASCII-encoded string.

   Added in version 3.2.

int PyErr_WarnExplicitFormat(PyObject *category, const char *filename, int lineno, const char *module, PyObject *registry, const char *format, ...)

   Similar to "PyErr_WarnExplicit()", but uses
   "PyUnicode_FromFormat()" to format the warning message. *format* is
   an ASCII-encoded string.

   Added in version 3.2.

int PyErr_ResourceWarning(PyObject *source, Py_ssize_t stack_level, const char *format, ...)
    * Part of the Stable ABI since version 3.6.*

   Function similar to "PyErr_WarnFormat()", but *category* is
   "ResourceWarning" and it passes *source* to
   "warnings.WarningMessage".

   Added in version 3.6.


Querying the error indicator
============================

PyObject *PyErr_Occurred()
    *Return value: Borrowed reference.** Part of the Stable ABI.*

   Test whether the error indicator is set.  If set, return the
   exception *type* (the first argument to the last call to one of the
   "PyErr_Set*" functions or to "PyErr_Restore()").  If not set,
   return "NULL".  You do not own a reference to the return value, so
   you do not need to "Py_DECREF()" it.

   The caller must have an *attached thread state*.

   Note:

     Do not compare the return value to a specific exception; use
     "PyErr_ExceptionMatches()" instead, shown below.  (The comparison
     could easily fail since the exception may be an instance instead
     of a class, in the case of a class exception, or it may be a
     subclass of the expected exception.)

int PyErr_ExceptionMatches(PyObject *exc)
    * Part of the Stable ABI.*

   Equivalent to "PyErr_GivenExceptionMatches(PyErr_Occurred(), exc)".
   This should only be called when an exception is actually set; a
   memory access violation will occur if no exception has been raised.

int PyErr_GivenExceptionMatches(PyObject *given, PyObject *exc)
    * Part of the Stable ABI.*

   Return true if the *given* exception matches the exception type in
   *exc*.  If *exc* is a class object, this also returns true when
   *given* is an instance of a subclass.  If *exc* is a tuple, all
   exception types in the tuple (and recursively in subtuples) are
   searched for a match.

PyObject *PyErr_GetRaisedException(void)
    *Return value: New reference.** Part of the Stable ABI since
   version 3.12.*

   Return the exception currently being raised, clearing the error
   indicator at the same time. Return "NULL" if the error indicator is
   not set.

   This function is used by code that needs to catch exceptions, or
   code that needs to save and restore the error indicator
   temporarily.

   For example:

      {
         PyObject *exc = PyErr_GetRaisedException();

         /* ... code that might produce other errors ... */

         PyErr_SetRaisedException(exc);
      }

   See also:

     "PyErr_GetHandledException()", to save the exception currently
     being handled.

   Added in version 3.12.

void PyErr_SetRaisedException(PyObject *exc)
    * Part of the Stable ABI since version 3.12.*

   Set *exc* as the exception currently being raised, clearing the
   existing exception if one is set.

   Warning:

     This call steals a reference to *exc*, which must be a valid
     exception.

   Added in version 3.12.

void PyErr_Fetch(PyObject **ptype, PyObject **pvalue, PyObject **ptraceback)
    * Part of the Stable ABI.*

   Deprecated since version 3.12: Use "PyErr_GetRaisedException()"
   instead.

   Retrieve the error indicator into three variables whose addresses
   are passed. If the error indicator is not set, set all three
   variables to "NULL".  If it is set, it will be cleared and you own
   a reference to each object retrieved.  The value and traceback
   object may be "NULL" even when the type object is not.

   Note:

     This function is normally only used by legacy code that needs to
     catch exceptions or save and restore the error indicator
     temporarily.For example:

        {
           PyObject *type, *value, *traceback;
           PyErr_Fetch(&type, &value, &traceback);

           /* ... code that might produce other errors ... */

           PyErr_Restore(type, value, traceback);
        }

void PyErr_Restore(PyObject *type, PyObject *value, PyObject *traceback)
    * Part of the Stable ABI.*

   Deprecated since version 3.12: Use "PyErr_SetRaisedException()"
   instead.

   Set the error indicator from the three objects, *type*, *value*,
   and *traceback*, clearing the existing exception if one is set. If
   the objects are "NULL", the error indicator is cleared.  Do not
   pass a "NULL" type and non-"NULL" value or traceback.  The
   exception type should be a class.  Do not pass an invalid exception
   type or value. (Violating these rules will cause subtle problems
   later.)  This call takes away a reference to each object: you must
   own a reference to each object before the call and after the call
   you no longer own these references.  (If you don't understand this,
   don't use this function.  I warned you.)

   Note:

     This function is normally only used by legacy code that needs to
     save and restore the error indicator temporarily. Use
     "PyErr_Fetch()" to save the current error indicator.

void PyErr_NormalizeException(PyObject **exc, PyObject **val, PyObject **tb)
    * Part of the Stable ABI.*

   Deprecated since version 3.12: Use "PyErr_GetRaisedException()"
   instead, to avoid any possible de-normalization.

   Under certain circumstances, the values returned by "PyErr_Fetch()"
   below can be "unnormalized", meaning that "*exc" is a class object
   but "*val" is not an instance of the  same class.  This function
   can be used to instantiate the class in that case.  If the values
   are already normalized, nothing happens. The delayed normalization
   is implemented to improve performance.

   Note:

     This function *does not* implicitly set the "__traceback__"
     attribute on the exception value. If setting the traceback
     appropriately is desired, the following additional snippet is
     needed:

        if (tb != NULL) {
          PyException_SetTraceback(val, tb);
        }

PyObject *PyErr_GetHandledException(void)
    * Part of the Stable ABI since version 3.11.*

   Retrieve the active exception instance, as would be returned by
   "sys.exception()". This refers to an exception that was *already
   caught*, not to an exception that was freshly raised. Returns a new
   reference to the exception or "NULL". Does not modify the
   interpreter's exception state.

   Note:

     This function is not normally used by code that wants to handle
     exceptions. Rather, it can be used when code needs to save and
     restore the exception state temporarily.  Use
     "PyErr_SetHandledException()" to restore or clear the exception
     state.

   Added in version 3.11.

void PyErr_SetHandledException(PyObject *exc)
    * Part of the Stable ABI since version 3.11.*

   Set the active exception, as known from "sys.exception()".  This
   refers to an exception that was *already caught*, not to an
   exception that was freshly raised. To clear the exception state,
   pass "NULL".

   Note:

     This function is not normally used by code that wants to handle
     exceptions. Rather, it can be used when code needs to save and
     restore the exception state temporarily.  Use
     "PyErr_GetHandledException()" to get the exception state.

   Added in version 3.11.

void PyErr_GetExcInfo(PyObject **ptype, PyObject **pvalue, PyObject **ptraceback)
    * Part of the Stable ABI since version 3.7.*

   Retrieve the old-style representation of the exception info, as
   known from "sys.exc_info()".  This refers to an exception that was
   *already caught*, not to an exception that was freshly raised.
   Returns new references for the three objects, any of which may be
   "NULL".  Does not modify the exception info state.  This function
   is kept for backwards compatibility. Prefer using
   "PyErr_GetHandledException()".

   Note:

     This function is not normally used by code that wants to handle
     exceptions. Rather, it can be used when code needs to save and
     restore the exception state temporarily.  Use
     "PyErr_SetExcInfo()" to restore or clear the exception state.

   Added in version 3.3.

void PyErr_SetExcInfo(PyObject *type, PyObject *value, PyObject *traceback)
    * Part of the Stable ABI since version 3.7.*

   Set the exception info, as known from "sys.exc_info()".  This
   refers to an exception that was *already caught*, not to an
   exception that was freshly raised.  This function steals the
   references of the arguments. To clear the exception state, pass
   "NULL" for all three arguments. This function is kept for backwards
   compatibility. Prefer using "PyErr_SetHandledException()".

   Note:

     This function is not normally used by code that wants to handle
     exceptions. Rather, it can be used when code needs to save and
     restore the exception state temporarily.  Use
     "PyErr_GetExcInfo()" to read the exception state.

   Added in version 3.3.

   Changed in version 3.11: The "type" and "traceback" arguments are
   no longer used and can be NULL. The interpreter now derives them
   from the exception instance (the "value" argument). The function
   still steals references of all three arguments.


Signal Handling
===============

int PyErr_CheckSignals()
    * Part of the Stable ABI.*

   Handle external interruptions, such as signals or activating a
   debugger, whose processing has been delayed until it is safe to run
   Python code and/or raise exceptions.

   For example, pressing "Ctrl"-"C" causes a terminal to send the
   "signal.SIGINT" signal. This function executes the corresponding
   Python signal handler, which, by default, raises the
   "KeyboardInterrupt" exception.

   "PyErr_CheckSignals()" should be called by long-running C code
   frequently enough so that the response appears immediate to humans.

   Handlers invoked by this function currently include:

   * Signal handlers, including Python functions registered using the
     "signal" module.

     Signal handlers are only run in the main thread of the main
     interpreter.

     (This is where the function got the name: originally, signals
     were the only way to interrupt the interpreter.)

   * Running the garbage collector, if necessary.

   * Executing a pending remote debugger script.

   * Raise the exception set by "PyThreadState_SetAsyncExc()".

   If any handler raises an exception, immediately return "-1" with
   that exception set. Any remaining interruptions are left to be
   processed on the next "PyErr_CheckSignals()" invocation, if
   appropriate.

   If all handlers finish successfully, or there are no handlers to
   run, return "0".

   Changed in version 3.12: This function may now invoke the garbage
   collector.

   Changed in version 3.14: This function may now execute a remote
   debugger script, if remote debugging is enabled.

   Changed in version 3.15: The exception set by
   "PyThreadState_SetAsyncExc()" is now raised.

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

   Simulate the effect of a "SIGINT" signal arriving. This is
   equivalent to "PyErr_SetInterruptEx(SIGINT)".

   Note:

     This function is async-signal-safe.  It can be called without an
     *attached thread state* and from a C signal handler.

int PyErr_SetInterruptEx(int signum)
    * Part of the Stable ABI since version 3.10.*

   Simulate the effect of a signal arriving. The next time
   "PyErr_CheckSignals()" is called,  the Python signal handler for
   the given signal number will be called.

   This function can be called by C code that sets up its own signal
   handling and wants Python signal handlers to be invoked as expected
   when an interruption is requested (for example when the user
   presses Ctrl-C to interrupt an operation).

   If the given signal isn't handled by Python (it was set to
   "signal.SIG_DFL" or "signal.SIG_IGN"), it will be ignored.

   If *signum* is outside of the allowed range of signal numbers, "-1"
   is returned.  Otherwise, "0" is returned.  The error indicator is
   never changed by this function.

   Note:

     This function is async-signal-safe.  It can be called without an
     *attached thread state* and from a C signal handler.

   Added in version 3.10.

int PySignal_SetWakeupFd(int fd)

   This utility function specifies a file descriptor to which the
   signal number is written as a single byte whenever a signal is
   received. *fd* must be non-blocking. It returns the previous such
   file descriptor.

   The value "-1" disables the feature; this is the initial state.
   This is equivalent to "signal.set_wakeup_fd()" in Python, but
   without any error checking.  *fd* should be a valid file
   descriptor.  The function should only be called from the main
   thread.

   Changed in version 3.5: On Windows, the function now also supports
   socket handles.


Exception Classes
=================

PyObject *PyErr_NewException(const char *name, PyObject *base, PyObject *dict)
    *Return value: New reference.** Part of the Stable ABI.*

   This utility function creates and returns a new exception class.
   The *name* argument must be the name of the new exception, a C
   string of the form "module.classname".  The *base* and *dict*
   arguments are normally "NULL". This creates a class object derived
   from "Exception" (accessible in C as "PyExc_Exception").

   The "__module__" attribute of the new class is set to the first
   part (up to the last dot) of the *name* argument, and the class
   name is set to the last part (after the last dot).  The *base*
   argument can be used to specify alternate base classes; it can
   either be only one class or a tuple of classes. The *dict* argument
   can be used to specify a dictionary of class variables and methods.

PyObject *PyErr_NewExceptionWithDoc(const char *name, const char *doc, PyObject *base, PyObject *dict)
    *Return value: New reference.** Part of the Stable ABI.*

   Same as "PyErr_NewException()", except that the new exception class
   can easily be given a docstring: If *doc* is non-"NULL", it will be
   used as the docstring for the exception class.

   Added in version 3.2.

int PyExceptionClass_Check(PyObject *ob)

   Return non-zero if *ob* is an exception class, zero otherwise. This
   function always succeeds.

const char *PyExceptionClass_Name(PyObject *ob)
    * Part of the Stable ABI since version 3.8.*

   Return "tp_name" of the exception class *ob*.

PyException_HEAD

   This is a macro including the base fields for an exception object.

   This was included in Python's C API by mistake and is not designed
   for use in extensions. For creating custom exception objects, use
   "PyErr_NewException()" or otherwise create a class inheriting from
   "PyExc_BaseException".

   Soft deprecated since version 3.15.


Exception Objects
=================

int PyExceptionInstance_Check(PyObject *op)

   Return true if *op* is an instance of "BaseException", false
   otherwise. This function always succeeds.

PyExceptionInstance_Class(op)

   Equivalent to "Py_TYPE(op)".

PyObject *PyException_GetTraceback(PyObject *ex)
    *Return value: New reference.** Part of the Stable ABI.*

   Return the traceback associated with the exception as a new
   reference, as accessible from Python through the "__traceback__"
   attribute. If there is no traceback associated, this returns
   "NULL".

int PyException_SetTraceback(PyObject *ex, PyObject *tb)
    * Part of the Stable ABI.*

   Set the traceback associated with the exception to *tb*.  Use
   "Py_None" to clear it.

PyObject *PyException_GetContext(PyObject *ex)
    *Return value: New reference.** Part of the Stable ABI.*

   Return the context (another exception instance during whose
   handling *ex* was raised) associated with the exception as a new
   reference, as accessible from Python through the "__context__"
   attribute. If there is no context associated, this returns "NULL".

void PyException_SetContext(PyObject *ex, PyObject *ctx)
    * Part of the Stable ABI.*

   Set the context associated with the exception to *ctx*.  Use "NULL"
   to clear it.  There is no type check to make sure that *ctx* is an
   exception instance. This steals a reference to *ctx*.

PyObject *PyException_GetCause(PyObject *ex)
    *Return value: New reference.** Part of the Stable ABI.*

   Return the cause (either an exception instance, or "None", set by
   "raise ... from ...") associated with the exception as a new
   reference, as accessible from Python through the "__cause__"
   attribute.

void PyException_SetCause(PyObject *ex, PyObject *cause)
    * Part of the Stable ABI.*

   Set the cause associated with the exception to *cause*.  Use "NULL"
   to clear it.  There is no type check to make sure that *cause* is
   either an exception instance or "None".  This steals a reference to
   *cause*.

   The "__suppress_context__" attribute is implicitly set to "True" by
   this function.

PyObject *PyException_GetArgs(PyObject *ex)
    *Return value: New reference.** Part of the Stable ABI since
   version 3.12.*

   Return "args" of exception *ex*.

void PyException_SetArgs(PyObject *ex, PyObject *args)
    * Part of the Stable ABI since version 3.12.*

   Set "args" of exception *ex* to *args*.

PyObject *PyUnstable_Exc_PrepReraiseStar(PyObject *orig, PyObject *excs)

   *This is Unstable API. It may change without warning in minor
   releases.*

   Implement part of the interpreter's implementation of "except*".
   *orig* is the original exception that was caught, and *excs* is the
   list of the exceptions that need to be raised. This list contains
   the unhandled part of *orig*, if any, as well as the exceptions
   that were raised from the "except*" clauses (so they have a
   different traceback from *orig*) and those that were reraised (and
   have the same traceback as *orig*). Return the "ExceptionGroup"
   that needs to be reraised in the end, or "None" if there is nothing
   to reraise.

   Added in version 3.12.


Unicode Exception Objects
=========================

The following functions are used to create and modify Unicode
exceptions from C.

PyObject *PyUnicodeDecodeError_Create(const char *encoding, const char *object, Py_ssize_t length, Py_ssize_t start, Py_ssize_t end, const char *reason)
    *Return value: New reference.** Part of the Stable ABI.*

   Create a "UnicodeDecodeError" object with the attributes
   *encoding*, *object*, *length*, *start*, *end* and *reason*.
   *encoding* and *reason* are UTF-8 encoded strings.

PyObject *PyUnicodeDecodeError_GetEncoding(PyObject *exc)
PyObject *PyUnicodeEncodeError_GetEncoding(PyObject *exc)
    *Return value: New reference.** Part of the Stable ABI.*

   Return the *encoding* attribute of the given exception object.

PyObject *PyUnicodeDecodeError_GetObject(PyObject *exc)
PyObject *PyUnicodeEncodeError_GetObject(PyObject *exc)
PyObject *PyUnicodeTranslateError_GetObject(PyObject *exc)
    *Return value: New reference.** Part of the Stable ABI.*

   Return the *object* attribute of the given exception object.

int PyUnicodeDecodeError_GetStart(PyObject *exc, Py_ssize_t *start)
int PyUnicodeEncodeError_GetStart(PyObject *exc, Py_ssize_t *start)
int PyUnicodeTranslateError_GetStart(PyObject *exc, Py_ssize_t *start)
    * Part of the Stable ABI.*

   Get the *start* attribute of the given exception object and place
   it into **start*.  *start* must not be "NULL".  Return "0" on
   success, "-1" on failure.

   If the "UnicodeError.object" is an empty sequence, the resulting
   *start* is "0". Otherwise, it is clipped to "[0, len(object) - 1]".

   See also: "UnicodeError.start"

int PyUnicodeDecodeError_SetStart(PyObject *exc, Py_ssize_t start)
int PyUnicodeEncodeError_SetStart(PyObject *exc, Py_ssize_t start)
int PyUnicodeTranslateError_SetStart(PyObject *exc, Py_ssize_t start)
    * Part of the Stable ABI.*

   Set the *start* attribute of the given exception object to *start*.
   Return "0" on success, "-1" on failure.

   Note:

     While passing a negative *start* does not raise an exception, the
     corresponding getters will not consider it as a relative offset.

int PyUnicodeDecodeError_GetEnd(PyObject *exc, Py_ssize_t *end)
int PyUnicodeEncodeError_GetEnd(PyObject *exc, Py_ssize_t *end)
int PyUnicodeTranslateError_GetEnd(PyObject *exc, Py_ssize_t *end)
    * Part of the Stable ABI.*

   Get the *end* attribute of the given exception object and place it
   into **end*.  *end* must not be "NULL".  Return "0" on success,
   "-1" on failure.

   If the "UnicodeError.object" is an empty sequence, the resulting
   *end* is "0". Otherwise, it is clipped to "[1, len(object)]".

int PyUnicodeDecodeError_SetEnd(PyObject *exc, Py_ssize_t end)
int PyUnicodeEncodeError_SetEnd(PyObject *exc, Py_ssize_t end)
int PyUnicodeTranslateError_SetEnd(PyObject *exc, Py_ssize_t end)
    * Part of the Stable ABI.*

   Set the *end* attribute of the given exception object to *end*.
   Return "0" on success, "-1" on failure.

   See also: "UnicodeError.end"

PyObject *PyUnicodeDecodeError_GetReason(PyObject *exc)
PyObject *PyUnicodeEncodeError_GetReason(PyObject *exc)
PyObject *PyUnicodeTranslateError_GetReason(PyObject *exc)
    *Return value: New reference.** Part of the Stable ABI.*

   Return the *reason* attribute of the given exception object.

int PyUnicodeDecodeError_SetReason(PyObject *exc, const char *reason)
int PyUnicodeEncodeError_SetReason(PyObject *exc, const char *reason)
int PyUnicodeTranslateError_SetReason(PyObject *exc, const char *reason)
    * Part of the Stable ABI.*

   Set the *reason* attribute of the given exception object to
   *reason*.  Return "0" on success, "-1" on failure.


Recursion Control
=================

These two functions provide a way to perform safe recursive calls at
the C level, both in the core and in extension modules.  They are
needed if the recursive code does not necessarily invoke Python code
(which tracks its recursion depth automatically). They are also not
needed for *tp_call* implementations because the call protocol takes
care of recursion handling.

int Py_EnterRecursiveCall(const char *where)
    * Part of the Stable ABI since version 3.9.*

   Marks a point where a recursive C-level call is about to be
   performed.

   The function then checks if the stack limit is reached.  If this is
   the case, a "RecursionError" is set and a nonzero value is
   returned. Otherwise, zero is returned.

   *where* should be a UTF-8 encoded string such as "" in instance
   check"" to be concatenated to the "RecursionError" message caused
   by the recursion depth limit.

   See also:

     The "PyUnstable_ThreadState_SetStackProtection()" function.

   Changed in version 3.9: This function is now also available in the
   limited API.

void Py_LeaveRecursiveCall(void)
    * Part of the Stable ABI since version 3.9.*

   Ends a "Py_EnterRecursiveCall()".  Must be called once for each
   *successful* invocation of "Py_EnterRecursiveCall()".

   Changed in version 3.9: This function is now also available in the
   limited API.

Properly implementing "tp_repr" for container types requires special
recursion handling.  In addition to protecting the stack, "tp_repr"
also needs to track objects to prevent cycles.  The following two
functions facilitate this functionality.  Effectively, these are the C
equivalent to "reprlib.recursive_repr()".

int Py_ReprEnter(PyObject *object)
    * Part of the Stable ABI.*

   Called at the beginning of the "tp_repr" implementation to detect
   cycles.

   If the object has already been processed, the function returns a
   positive integer.  In that case the "tp_repr" implementation should
   return a string object indicating a cycle.  As examples, "dict"
   objects return "{...}" and "list" objects return "[...]".

   The function will return a negative integer if the recursion limit
   is reached.  In that case the "tp_repr" implementation should
   typically return "NULL".

   Otherwise, the function returns zero and the "tp_repr"
   implementation can continue normally.

void Py_ReprLeave(PyObject *object)
    * Part of the Stable ABI.*

   Ends a "Py_ReprEnter()".  Must be called once for each invocation
   of "Py_ReprEnter()" that returns zero.

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

   Get the recursion limit for the current interpreter. It can be set
   with "Py_SetRecursionLimit()". The recursion limit prevents the
   Python interpreter stack from growing infinitely.

   This function cannot fail, and the caller must hold an *attached
   thread state*.

   See also: "sys.getrecursionlimit()"

void Py_SetRecursionLimit(int new_limit)
    * Part of the Stable ABI.*

   Set the recursion limit for the current interpreter.

   This function cannot fail, and the caller must hold an *attached
   thread state*.

   See also: "sys.setrecursionlimit()"


Exception and warning types
===========================

All standard Python exceptions and warning categories are available as
global variables whose names are "PyExc_" followed by the Python
exception name. These have the type PyObject*; they are all class
objects.

For completeness, here are all the variables:


Exception types
---------------

+----------------------------------------------------+----------------------------------------------------+
| C name                                             | Python name                                        |
|====================================================|====================================================|
| PyObject *PyExc_BaseException  * Part of the       | "BaseException"                                    |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_BaseExceptionGroup  * Part of the  | "BaseExceptionGroup"                               |
| Stable ABI since version 3.11.*                    |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_Exception  * Part of the Stable    | "Exception"                                        |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ArithmeticError  * Part of the     | "ArithmeticError"                                  |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_AssertionError  * Part of the      | "AssertionError"                                   |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_AttributeError  * Part of the      | "AttributeError"                                   |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_BlockingIOError  * Part of the     | "BlockingIOError"                                  |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_BrokenPipeError  * Part of the     | "BrokenPipeError"                                  |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_BufferError  * Part of the Stable  | "BufferError"                                      |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ChildProcessError  * Part of the   | "ChildProcessError"                                |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ConnectionAbortedError  * Part of  | "ConnectionAbortedError"                           |
| the Stable ABI since version 3.7.*                 |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ConnectionError  * Part of the     | "ConnectionError"                                  |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ConnectionRefusedError  * Part of  | "ConnectionRefusedError"                           |
| the Stable ABI since version 3.7.*                 |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ConnectionResetError  * Part of    | "ConnectionResetError"                             |
| the Stable ABI since version 3.7.*                 |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_EOFError  * Part of the Stable     | "EOFError"                                         |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_FileExistsError  * Part of the     | "FileExistsError"                                  |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_FileNotFoundError  * Part of the   | "FileNotFoundError"                                |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_FloatingPointError  * Part of the  | "FloatingPointError"                               |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_GeneratorExit  * Part of the       | "GeneratorExit"                                    |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ImportCycleError                   | "ImportCycleError"                                 |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ImportError  * Part of the Stable  | "ImportError"                                      |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_IndentationError  * Part of the    | "IndentationError"                                 |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_IndexError  * Part of the Stable   | "IndexError"                                       |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_InterruptedError  * Part of the    | "InterruptedError"                                 |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_IsADirectoryError  * Part of the   | "IsADirectoryError"                                |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_KeyError  * Part of the Stable     | "KeyError"                                         |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_KeyboardInterrupt  * Part of the   | "KeyboardInterrupt"                                |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_LookupError  * Part of the Stable  | "LookupError"                                      |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_MemoryError  * Part of the Stable  | "MemoryError"                                      |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ModuleNotFoundError  * Part of the | "ModuleNotFoundError"                              |
| Stable ABI since version 3.6.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_NameError  * Part of the Stable    | "NameError"                                        |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_NotADirectoryError  * Part of the  | "NotADirectoryError"                               |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_NotImplementedError  * Part of the | "NotImplementedError"                              |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_OSError  * Part of the Stable      | "OSError"                                          |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_OverflowError  * Part of the       | "OverflowError"                                    |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_PermissionError  * Part of the     | "PermissionError"                                  |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ProcessLookupError  * Part of the  | "ProcessLookupError"                               |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_PythonFinalizationError            | "PythonFinalizationError"                          |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_RecursionError  * Part of the      | "RecursionError"                                   |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ReferenceError  * Part of the      | "ReferenceError"                                   |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_RuntimeError  * Part of the Stable | "RuntimeError"                                     |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_StopAsyncIteration  * Part of the  | "StopAsyncIteration"                               |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_StopIteration  * Part of the       | "StopIteration"                                    |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_SyntaxError  * Part of the Stable  | "SyntaxError"                                      |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_SystemError  * Part of the Stable  | "SystemError"                                      |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_SystemExit  * Part of the Stable   | "SystemExit"                                       |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_TabError  * Part of the Stable     | "TabError"                                         |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_TimeoutError  * Part of the Stable | "TimeoutError"                                     |
| ABI since version 3.7.*                            |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_TypeError  * Part of the Stable    | "TypeError"                                        |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_UnboundLocalError  * Part of the   | "UnboundLocalError"                                |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_UnicodeDecodeError  * Part of the  | "UnicodeDecodeError"                               |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_UnicodeEncodeError  * Part of the  | "UnicodeEncodeError"                               |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_UnicodeError  * Part of the Stable | "UnicodeError"                                     |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_UnicodeTranslateError  * Part of   | "UnicodeTranslateError"                            |
| the Stable ABI.*                                   |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ValueError  * Part of the Stable   | "ValueError"                                       |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ZeroDivisionError  * Part of the   | "ZeroDivisionError"                                |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+

Added in version 3.3: "PyExc_BlockingIOError",
"PyExc_BrokenPipeError", "PyExc_ChildProcessError",
"PyExc_ConnectionError", "PyExc_ConnectionAbortedError",
"PyExc_ConnectionRefusedError", "PyExc_ConnectionResetError",
"PyExc_FileExistsError", "PyExc_FileNotFoundError",
"PyExc_InterruptedError", "PyExc_IsADirectoryError",
"PyExc_NotADirectoryError", "PyExc_PermissionError",
"PyExc_ProcessLookupError" and "PyExc_TimeoutError" were introduced
following **PEP 3151**.

Added in version 3.5: "PyExc_StopAsyncIteration" and
"PyExc_RecursionError".

Added in version 3.6: "PyExc_ModuleNotFoundError".

Added in version 3.11: "PyExc_BaseExceptionGroup".


OSError aliases
---------------

The following are a compatibility aliases to "PyExc_OSError".

Changed in version 3.3: These aliases used to be separate exception
types.

+-----------------------------------+-----------------------------------+-----------------------------------+
| C name                            | Python name                       | Notes                             |
|===================================|===================================|===================================|
| PyObject *PyExc_EnvironmentError  | "OSError"                         |                                   |
| * Part of the Stable ABI.*        |                                   |                                   |
+-----------------------------------+-----------------------------------+-----------------------------------+
| PyObject *PyExc_IOError  * Part   | "OSError"                         |                                   |
| of the Stable ABI.*               |                                   |                                   |
+-----------------------------------+-----------------------------------+-----------------------------------+
| PyObject *PyExc_WindowsError  *   | "OSError"                         | [win]                             |
| Part of the Stable ABI on Windows |                                   |                                   |
| since version 3.7.*               |                                   |                                   |
+-----------------------------------+-----------------------------------+-----------------------------------+

Notes:

[win] "PyExc_WindowsError" is only defined on Windows; protect code
      that uses this by testing that the preprocessor macro
      "MS_WINDOWS" is defined.


Warning types
-------------

+----------------------------------------------------+----------------------------------------------------+
| C name                                             | Python name                                        |
|====================================================|====================================================|
| PyObject *PyExc_Warning  * Part of the Stable      | "Warning"                                          |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_BytesWarning  * Part of the Stable | "BytesWarning"                                     |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_DeprecationWarning  * Part of the  | "DeprecationWarning"                               |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_EncodingWarning  * Part of the     | "EncodingWarning"                                  |
| Stable ABI since version 3.10.*                    |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_FutureWarning  * Part of the       | "FutureWarning"                                    |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ImportWarning  * Part of the       | "ImportWarning"                                    |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_PendingDeprecationWarning  * Part  | "PendingDeprecationWarning"                        |
| of the Stable ABI.*                                |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_ResourceWarning  * Part of the     | "ResourceWarning"                                  |
| Stable ABI since version 3.7.*                     |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_RuntimeWarning  * Part of the      | "RuntimeWarning"                                   |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_SyntaxWarning  * Part of the       | "SyntaxWarning"                                    |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_UnicodeWarning  * Part of the      | "UnicodeWarning"                                   |
| Stable ABI.*                                       |                                                    |
+----------------------------------------------------+----------------------------------------------------+
| PyObject *PyExc_UserWarning  * Part of the Stable  | "UserWarning"                                      |
| ABI.*                                              |                                                    |
+----------------------------------------------------+----------------------------------------------------+

Added in version 3.2: "PyExc_ResourceWarning".

Added in version 3.10: "PyExc_EncodingWarning".


Tracebacks
==========

PyTypeObject PyTraceBack_Type
    * Part of the Stable ABI.*

   Type object for traceback objects. This is available as
   "types.TracebackType" in the Python layer.

int PyTraceBack_Check(PyObject *op)

   Return true if *op* is a traceback object, false otherwise. This
   function does not account for subtypes.

int PyTraceBack_Here(PyFrameObject *f)
    * Part of the Stable ABI.*

   Replace the "__traceback__" attribute on the current exception with
   a new traceback prepending *f* to the existing chain.

   Calling this function without an exception set is undefined
   behavior.

   This function returns "0" on success, and returns "-1" with an
   exception set on failure.

int PyTraceBack_Print(PyObject *tb, PyObject *f)
    * Part of the Stable ABI.*

   Write the traceback *tb* into the file *f*.

   This function returns "0" on success, and returns "-1" with an
   exception set on failure.

const char *PyUnstable_DumpTraceback(int fd, PyThreadState *tstate)

   *This is Unstable API. It may change without warning in minor
   releases.*

   Write a trace of the Python stack in *tstate* into the file *fd*.
   The format looks like:

      Traceback (most recent call first):
        File "xxx", line xxx in <xxx>
        File "xxx", line xxx in <xxx>
        ...
        File "xxx", line xxx in <xxx>

   This function is meant to debug situations such as segfaults, fatal
   errors, and similar. The file and function names it outputs are
   encoded to ASCII with backslashreplace and truncated to 500
   characters. It writes only the first 100 frames; further frames are
   truncated with the line "...".

   This function will return "NULL" on success, or an error message on
   error.

   This function is intended for use in crash scenarios such as signal
   handlers for SIGSEGV, where the interpreter may be in an
   inconsistent state. Given that it reads interpreter data structures
   that may be partially modified, the function might produce
   incomplete output or it may even crash itself.

   The caller does not need to hold an *attached thread state*, nor
   does *tstate* need to be attached.

   Added in version 3.15.

const char *PyUnstable_DumpTracebackThreads(int fd, PyInterpreterState *interp, PyThreadState *current_tstate, Py_ssize_t max_threads)

   *This is Unstable API. It may change without warning in minor
   releases.*

   Write the traces of all Python threads in *interp* into the file
   *fd*.

   If *interp* is "NULL" then this function will try to identify the
   current interpreter using thread-specific storage. If it cannot, it
   will return an error.

   If *current_tstate* is not "NULL" then it will be used to identify
   what the current thread is in the written output. If it is "NULL"
   then this function will identify the current thread using thread-
   specific storage. It is not an error if the function is unable to
   get the current Python thread state.

   This function will return "NULL" on success, or an error message on
   error.

   This function is meant to debug debug situations such as segfaults,
   fatal errors, and similar. It calls "PyUnstable_DumpTraceback()"
   for each thread. It only writes the tracebacks of the first
   *max_threads* threads, further output is truncated with the line
   "...". If *max_threads* is 0, the function will use a default value
   of 100 for the argument.

   This function is intended for use in crash scenarios such as signal
   handlers for SIGSEGV, where the interpreter may be in an
   inconsistent state. Given that it reads interpreter data structures
   that may be partially modified, the function might produce
   incomplete output or it may even crash itself.

   The caller does not need to hold an *attached thread state*, nor
   does *current_tstate* need to be attached.

   Warning:

     On the *free-threaded build*, this function is not thread-safe.
     If another thread deletes its *thread state* while this function
     is being called, the process will likely crash.

   Added in version 3.15.
