# Obsługa sytuacji wyjątkowych

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`).

Gdy zadanie musi zawieźć z powodu błędu zadania które wywołało, ogólnie nie ustawia ona wskaźnika błędu; podzadanie które zostało wywołane już go ustawiła. Jest on odpowiedzialny albo za obsługę błędu i wyczyszczenie wskaźnika sytuacji wyjątkowej lub powrót po sprzątnięciu jakichkolwiek zasobów które utrzymuje (takich jak odwołania do przedmiotów lub zajęte pamięci); nie powinien kontynuować zwyczajnie jeśli nie jest przygotowany do obsługi błędu. Jeśli kończy z powodu błędu, istotne jest zwrócenie uwagi wołającego że został zgłoszony błąd. Jeśli błąd nie jest obsługiwany lub propagowany właściwie, dodatkowe odwołania do sprzęgu języka pytonowskiego/C mogą nie zachowywać się tak, jak planowano i mogą zawieźć w nieoczekiwane sposoby.

Informacja

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()
  Część stabilnego ABI.

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

void PyErr_PrintEx(int set_sys_last_vars)
  Część stabilnego 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.

  Zmienione w wersji 3.12: The setting of `sys.last_exc` was added.

void PyErr_Print()
  Część stabilnego ABI.

  Alias for `PyErr_PrintEx(1)`.

void PyErr_WriteUnraisable(PyObject *obj)
  Część stabilnego 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.

  Zmienione w wersji 3.4: Print a traceback. Print only traceback if obj is `NULL`.

  Zmienione w wersji 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.

  Dodane w wersji 3.13.

void PyErr_DisplayException(PyObject *exc)
  Część stabilnego ABI od wersji 3.12.

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

  Dodane w wersji 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)
  Część stabilnego 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)
  Część stabilnego 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, ...)
  Wartość zwracana: zawsze NULL. Część stabilnego 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)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI od wersji 3.5.

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

  Dodane w wersji 3.5.

void PyErr_SetNone(PyObject *type)
  Część stabilnego ABI.

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

int PyErr_BadArgument()
  Część stabilnego 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()
  Wartość zwracana: zawsze NULL. Część stabilnego 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)
  Wartość zwracana: zawsze NULL. Część stabilnego 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)
  Wartość zwracana: zawsze NULL. Część stabilnego 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)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI od wersji 3.7.

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

  Dodane w wersji 3.4.

PyObject *PyErr_SetFromErrnoWithFilename(PyObject *type, const char *filename)
  Wartość zwracana: zawsze NULL. Część stabilnego 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)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI on Windows od wersji 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`.

  Dostępność: Windows.

PyObject *PyErr_SetExcFromWindowsErr(PyObject *type, int ierr)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI on Windows od wersji 3.7.

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

  Dostępność: Windows.

PyObject *PyErr_SetFromWindowsErrWithFilename(int ierr, const char *filename)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI on Windows od wersji 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.

  Dostępność: Windows.

PyObject *PyErr_SetExcFromWindowsErrWithFilenameObject(PyObject *type, int ierr, PyObject *filename)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI on Windows od wersji 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.

  Dostępność: Windows.

PyObject *PyErr_SetExcFromWindowsErrWithFilenameObjects(PyObject *type, int ierr, PyObject *filename, PyObject *filename2)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI on Windows od wersji 3.7.

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

  Dostępność: Windows.

  Dodane w wersji 3.4.

PyObject *PyErr_SetExcFromWindowsErrWithFilename(PyObject *type, int ierr, const char *filename)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI on Windows od wersji 3.7.

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

  Dostępność: Windows.

PyObject *PyErr_SetImportError(PyObject *msg, PyObject *name, PyObject *path)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI od wersji 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.

  Dodane w wersji 3.3.

PyObject *PyErr_SetImportErrorSubclass(PyObject *exception, PyObject *msg, PyObject *name, PyObject *path)
  Wartość zwracana: zawsze NULL. Część stabilnego ABI od wersji 3.6.

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

  Dodane w wersji 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`.

  Dodane w wersji 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.

  Dodane w wersji 3.10.

void PyErr_SyntaxLocationEx(const char *filename, int lineno, int col_offset)
  Część stabilnego ABI od wersji 3.7.

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

  Dodane w wersji 3.2.

void PyErr_SyntaxLocation(const char *filename, int lineno)
  Część stabilnego ABI.

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

void PyErr_BadInternalCall()
  Część stabilnego 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)
  Część stabilnego 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)
  Część stabilnego 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.

  Dodane w wersji 3.4.

int PyErr_WarnExplicit(PyObject *category, const char *message, const char *filename, int lineno, const char *module, PyObject *registry)
  Część stabilnego 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, ...)
  Część stabilnego ABI.

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

  Dodane w wersji 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.

  Dodane w wersji 3.2.

int PyErr_ResourceWarning(PyObject *source, Py_ssize_t stack_level, const char *format, ...)
  Część stabilnego ABI od wersji 3.6.

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

  Dodane w wersji 3.6.

## Querying the error indicator

PyObject *PyErr_Occurred()
  Wartość zwracana: pożyczona referencja. Część stabilnego 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.

  Informacja

  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)
  Część stabilnego 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)
  Część stabilnego 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)
  Wartość zwracana: nowa referencja. Część stabilnego ABI od wersji 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.

  Na przykład:

      {
         PyObject *exc = PyErr_GetRaisedException();

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

         PyErr_SetRaisedException(exc);
      }

  Zobacz także

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

  Dodane w wersji 3.12.

void PyErr_SetRaisedException(PyObject *exc)
  Część stabilnego ABI od wersji 3.12.

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

  Ostrzeżenie

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

  Dodane w wersji 3.12.

void PyErr_Fetch(PyObject **ptype, PyObject **pvalue, PyObject **ptraceback)
  Część stabilnego ABI.

  Niezalecane od wersji 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.

  Informacja

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

  Na przykład:

      {
         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)
  Część stabilnego ABI.

  Niezalecane od wersji 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.)

  Informacja

  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)
  Część stabilnego ABI.

  Niezalecane od wersji 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.

  Informacja

  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)
  Część stabilnego ABI od wersji 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.

  Informacja

  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.

  Dodane w wersji 3.11.

void PyErr_SetHandledException(PyObject *exc)
  Część stabilnego ABI od wersji 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`.

  Informacja

  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.

  Dodane w wersji 3.11.

void PyErr_GetExcInfo(PyObject **ptype, PyObject **pvalue, PyObject **ptraceback)
  Część stabilnego ABI od wersji 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()`.

  Informacja

  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.

  Dodane w wersji 3.3.

void PyErr_SetExcInfo(PyObject *type, PyObject *value, PyObject *traceback)
  Część stabilnego ABI od wersji 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()`.

  Informacja

  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.

  Dodane w wersji 3.3.

  Zmienione w wersji 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()
  Część stabilnego ABI.

  This function interacts with Python’s signal handling.

  If the function is called from the main thread and under the main Python interpreter, it checks whether a signal has been sent to the processes and if so, invokes the corresponding signal handler. If the `signal` module is supported, this can invoke a signal handler written in Python.

  The function attempts to handle all pending signals, and then returns `0`. However, if a Python signal handler raises an exception, the error indicator is set and the function returns `-1` immediately (such that other pending signals may not have been handled yet: they will be on the next `PyErr_CheckSignals()` invocation).

  If the function is called from a non-main thread, or under a non-main Python interpreter, it does nothing and returns `0`.

  This function can be called by long-running C code that wants to be interruptible by user requests (such as by pressing Ctrl-C).

  Informacja

  The default Python signal handler for `SIGINT` raises the `KeyboardInterrupt` exception.

void PyErr_SetInterrupt()
  Część stabilnego ABI.

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

  Informacja

  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)
  Część stabilnego ABI od wersji 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.

  Informacja

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

  Dodane w wersji 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.

  Zmienione w wersji 3.5: On Windows, the function now also supports socket handles.

## Exception Classes

PyObject *PyErr_NewException(const char *name, PyObject *base, PyObject *dict)
  Wartość zwracana: nowa referencja. Część stabilnego 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)
  Wartość zwracana: nowa referencja. Część stabilnego 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.

  Dodane w wersji 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)
  Część stabilnego ABI od wersji 3.8.

  Return `tp_name` of the exception class ob.

PyException_HEAD

  This is a soft deprecated 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`.

## Przedmioty Sytuacji Wyjątkowych

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)
  Wartość zwracana: nowa referencja. Część stabilnego 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)
  Część stabilnego ABI.

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

PyObject *PyException_GetContext(PyObject *ex)
  Wartość zwracana: nowa referencja. Część stabilnego 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)
  Część stabilnego 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)
  Wartość zwracana: nowa referencja. Część stabilnego 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)
  Część stabilnego 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)
  Wartość zwracana: nowa referencja. Część stabilnego ABI od wersji 3.12.

  Return `args` of exception ex.

void PyException_SetArgs(PyObject *ex, PyObject *args)
  Część stabilnego ABI od wersji 3.12.

  Set `args` of exception ex to args.

PyObject *PyUnstable_Exc_PrepReraiseStar(PyObject *orig, PyObject *excs)
  To jest niestabilne API. Może ulec zmianie bez ostrzeżenia w wydaniach minor.

  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.

  Dodane w wersji 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)
  Wartość zwracana: nowa referencja. Część stabilnego 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)
  Wartość zwracana: nowa referencja. Część stabilnego 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)
  Wartość zwracana: nowa referencja. Część stabilnego 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)
  Część stabilnego 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]`.

  Zobacz także

  `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)
  Część stabilnego ABI.

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

  Informacja

  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)
  Część stabilnego 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)
  Część stabilnego ABI.

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

  Zobacz także

  `UnicodeError.end`

PyObject *PyUnicodeDecodeError_GetReason(PyObject *exc)
PyObject *PyUnicodeEncodeError_GetReason(PyObject *exc)
PyObject *PyUnicodeTranslateError_GetReason(PyObject *exc)
  Wartość zwracana: nowa referencja. Część stabilnego 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)
  Część stabilnego ABI.

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

## Kontrola Rekursji

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)
  Część stabilnego ABI od wersji 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.

  Zobacz także

  The `PyUnstable_ThreadState_SetStackProtection()` function.

  Zmienione w wersji 3.9: This function is now also available in the limited API.

void Py_LeaveRecursiveCall(void)
  Część stabilnego ABI od wersji 3.9.

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

  Zmienione w wersji 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)
  Część stabilnego 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)
  Część stabilnego ABI.

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

int Py_GetRecursionLimit(void)
  Część stabilnego 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.

  Zobacz także

  `sys.getrecursionlimit()`

void Py_SetRecursionLimit(int new_limit)
  Część stabilnego ABI.

  Set the recursion limit for the current interpreter.

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

  Zobacz także

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

Dodane w wersji 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.

Dodane w wersji 3.5: `PyExc_StopAsyncIteration` and `PyExc_RecursionError`.

Dodane w wersji 3.6: `PyExc_ModuleNotFoundError`.

Dodane w wersji 3.11: `PyExc_BaseExceptionGroup`.

### OSError aliases

The following are a compatibility aliases to `PyExc_OSError`.

Zmienione w wersji 3.3: These aliases used to be separate exception types.

C name | Python name | Notatki
--- | --- | ---
PyObject *PyExc_EnvironmentError Część stabilnego ABI. | `OSError` |
PyObject *PyExc_IOError Część stabilnego ABI. | `OSError` |
PyObject *PyExc_WindowsError Część stabilnego ABI on Windows od wersji 3.7. | `OSError` | [win]

Uwagi:

[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 Część stabilnego ABI. | `Warning`
PyObject *PyExc_BytesWarning Część stabilnego ABI. | `BytesWarning`
PyObject *PyExc_DeprecationWarning Część stabilnego ABI. | `DeprecationWarning`
PyObject *PyExc_EncodingWarning Część stabilnego ABI od wersji 3.10. | `EncodingWarning`
PyObject *PyExc_FutureWarning Część stabilnego ABI. | `FutureWarning`
PyObject *PyExc_ImportWarning Część stabilnego ABI. | `ImportWarning`
PyObject *PyExc_PendingDeprecationWarning Część stabilnego ABI. | `PendingDeprecationWarning`
PyObject *PyExc_ResourceWarning Część stabilnego ABI od wersji 3.7. | `ResourceWarning`
PyObject *PyExc_RuntimeWarning Część stabilnego ABI. | `RuntimeWarning`
PyObject *PyExc_SyntaxWarning Część stabilnego ABI. | `SyntaxWarning`
PyObject *PyExc_UnicodeWarning Część stabilnego ABI. | `UnicodeWarning`
PyObject *PyExc_UserWarning Część stabilnego ABI. | `UserWarning`

Dodane w wersji 3.2: `PyExc_ResourceWarning`.

Dodane w wersji 3.10: `PyExc_EncodingWarning`.

## Tracebacks

PyTypeObject PyTraceBack_Type
  Część stabilnego 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)
  Część stabilnego 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)
  Część stabilnego ABI.

  Write the traceback tb into the file f.

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