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.

توجه

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()

قسمتی از ABI پایدار.

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

void PyErr_PrintEx(int set_sys_last_vars)

قسمتی از ABI پایدار.

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.

تغییر داده شده در نسخه 3.12: The setting of sys.last_exc was added.

void PyErr_Print()

قسمتی از ABI پایدار.

Alias for PyErr_PrintEx(1).

void PyErr_WriteUnraisable(PyObject *obj)

قسمتی از ABI پایدار.

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.

تغییر داده شده در نسخه 3.4: Print a traceback. Print only traceback if obj is NULL.

تغییر داده شده در نسخه 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)

قسمتی از ABI پایدار از نسخه‌ی 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)

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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, ...)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار.

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)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار از نسخه‌ی 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)

قسمتی از ABI پایدار.

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

int PyErr_BadArgument()

قسمتی از ABI پایدار.

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()

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار.

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)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار.

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)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار.

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)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار از نسخه‌ی 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)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار.

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)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار on Windows از نسخه‌ی 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.

در دسترس بودن: Windows.

PyObject *PyErr_SetExcFromWindowsErr(PyObject *type, int ierr)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار on Windows از نسخه‌ی 3.7.

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

در دسترس بودن: Windows.

PyObject *PyErr_SetFromWindowsErrWithFilename(int ierr, const char *filename)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار on Windows از نسخه‌ی 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.

در دسترس بودن: Windows.

PyObject *PyErr_SetExcFromWindowsErrWithFilenameObject(PyObject *type, int ierr, PyObject *filename)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار on Windows از نسخه‌ی 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.

در دسترس بودن: Windows.

PyObject *PyErr_SetExcFromWindowsErrWithFilenameObjects(PyObject *type, int ierr, PyObject *filename, PyObject *filename2)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار on Windows از نسخه‌ی 3.7.

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

در دسترس بودن: Windows.

Added in version 3.4.

PyObject *PyErr_SetExcFromWindowsErrWithFilename(PyObject *type, int ierr, const char *filename)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار on Windows از نسخه‌ی 3.7.

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

در دسترس بودن: Windows.

PyObject *PyErr_SetImportError(PyObject *msg, PyObject *name, PyObject *path)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار از نسخه‌ی 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)

مقدار بازگشتی: همیشه NULL. قسمتی از ABI پایدار از نسخه‌ی 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)

قسمتی از ABI پایدار از نسخه‌ی 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)

قسمتی از ABI پایدار.

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

void PyErr_BadInternalCall()

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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, ...)

قسمتی از ABI پایدار.

Function similar to PyErr_WarnEx(), but uses 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, ...)

قسمتی از ABI پایدار از نسخه‌ی 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()

مقدار بازگشتی: مرجع قرضی. قسمتی از ABI پایدار.

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.

توجه

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)

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار از نسخه‌ی 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);
}

همچنین ملاحظه نمائید

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

Added in version 3.12.

void PyErr_SetRaisedException(PyObject *exc)

قسمتی از ABI پایدار از نسخه‌ی 3.12.

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

هشدار

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)

قسمتی از ABI پایدار.

منسوخ شده از نسخه 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.

توجه

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)

قسمتی از ABI پایدار.

منسوخ شده از نسخه 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.)

توجه

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)

قسمتی از ABI پایدار.

منسوخ شده از نسخه 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.

توجه

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)

قسمتی از ABI پایدار از نسخه‌ی 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.

توجه

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)

قسمتی از ABI پایدار از نسخه‌ی 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.

توجه

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)

قسمتی از ABI پایدار از نسخه‌ی 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().

توجه

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)

قسمتی از ABI پایدار از نسخه‌ی 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().

توجه

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.

تغییر داده شده در نسخه 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()

قسمتی از ABI پایدار.

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.

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.

تغییر داده شده در نسخه 3.12: This function may now invoke the garbage collector.

تغییر داده شده در نسخه 3.14: This function may now execute a remote debugger script, if remote debugging is enabled.

void PyErr_SetInterrupt()

قسمتی از ABI پایدار.

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

توجه

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)

قسمتی از ABI پایدار از نسخه‌ی 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.

توجه

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.

تغییر داده شده در نسخه 3.5: On Windows, the function now also supports socket handles.

Exception Classes

PyObject *PyErr_NewException(const char *name, PyObject *base, PyObject *dict)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار.

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)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار از نسخه‌ی 3.8.

Return tp_name of the exception class ob.

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)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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

PyObject *PyException_GetContext(PyObject *ex)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار از نسخه‌ی 3.12.

Return args of exception ex.

void PyException_SetArgs(PyObject *ex, PyObject *args)

قسمتی از ABI پایدار از نسخه‌ی 3.12.

Set args of exception ex to args.

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

این است API ناپایداراین ممکن است بدون هشدار در نسخه‌های جزئی تغییر کند.

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)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار.

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)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار.

Return the encoding attribute of the given exception object.

PyObject *PyUnicodeDecodeError_GetObject(PyObject *exc)

PyObject *PyUnicodeEncodeError_GetObject(PyObject *exc)

PyObject *PyUnicodeTranslateError_GetObject(PyObject *exc)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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].

همچنین ملاحظه نمائید

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)

قسمتی از ABI پایدار.

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

توجه

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)

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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

همچنین ملاحظه نمائید

UnicodeError.end

PyObject *PyUnicodeDecodeError_GetReason(PyObject *exc)

PyObject *PyUnicodeEncodeError_GetReason(PyObject *exc)

PyObject *PyUnicodeTranslateError_GetReason(PyObject *exc)

مقدار بازگشتی: مرجع جدید. قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار از نسخه‌ی 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.

همچنین ملاحظه نمائید

The PyUnstable_ThreadState_SetStackProtection() function.

تغییر داده شده در نسخه 3.9: This function is now also available in the limited API.

void Py_LeaveRecursiveCall(void)

قسمتی از ABI پایدار از نسخه‌ی 3.9.

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

تغییر داده شده در نسخه 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)

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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

int Py_GetRecursionLimit(void)

قسمتی از ABI پایدار.

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.

همچنین ملاحظه نمائید

sys.getrecursionlimit()

void Py_SetRecursionLimit(int new_limit)

قسمتی از ABI پایدار.

Set the recursion limit for the current interpreter.

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

همچنین ملاحظه نمائید

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

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.

تغییر داده شده در نسخه 3.3: These aliases used to be separate exception types.

C name	Python name	Notes
PyObject *PyExc_EnvironmentError قسمتی از ABI پایدار.	OSError
PyObject *PyExc_IOError قسمتی از ABI پایدار.	OSError
PyObject *PyExc_WindowsError قسمتی از ABI پایدار on Windows از نسخه‌ی 3.7.	OSError	[win]

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 قسمتی از ABI پایدار.	Warning
PyObject *PyExc_BytesWarning قسمتی از ABI پایدار.	BytesWarning
PyObject *PyExc_DeprecationWarning قسمتی از ABI پایدار.	DeprecationWarning
PyObject *PyExc_EncodingWarning قسمتی از ABI پایدار از نسخه‌ی 3.10.	EncodingWarning
PyObject *PyExc_FutureWarning قسمتی از ABI پایدار.	FutureWarning
PyObject *PyExc_ImportWarning قسمتی از ABI پایدار.	ImportWarning
PyObject *PyExc_PendingDeprecationWarning قسمتی از ABI پایدار.	PendingDeprecationWarning
PyObject *PyExc_ResourceWarning قسمتی از ABI پایدار از نسخه‌ی 3.7.	ResourceWarning
PyObject *PyExc_RuntimeWarning قسمتی از ABI پایدار.	RuntimeWarning
PyObject *PyExc_SyntaxWarning قسمتی از ABI پایدار.	SyntaxWarning
PyObject *PyExc_UnicodeWarning قسمتی از ABI پایدار.	UnicodeWarning
PyObject *PyExc_UserWarning قسمتی از ABI پایدار.	UserWarning

Added in version 3.2: PyExc_ResourceWarning.

Added in version 3.10: PyExc_EncodingWarning.

Tracebacks

PyTypeObject PyTraceBack_Type

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

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)

قسمتی از ABI پایدار.

Write the traceback tb into the file f.

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