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- from .object cimport PyObject
- cdef extern from "Python.h":
- #####################################################################
- # 3. 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 Unix errno variable: there is a global indicator (per
- # thread) of the last error that occurred. Most functions don't
- # clear this on success, but will set it to indicate the cause of
- # the error on failure. Most 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).
- # 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.
- # The error indicator consists of three Python objects
- # corresponding to the Python variables sys.exc_type,
- # sys.exc_value and sys.exc_traceback. API functions exist to
- # interact with the error indicator in various ways. There is a
- # separate error indicator for each thread.
- void PyErr_Print()
- # Print a standard traceback to sys.stderr and clear the error
- # indicator. Call this function only when the error indicator is
- # set. (Otherwise it will cause a fatal error!)
- PyObject* PyErr_Occurred()
- # Return value: Borrowed reference.
- # 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. Note: Do not compare the
- # return value to a specific exception; use
- # PyErr_ExceptionMatches() instead, shown below. (The comparison
- # could easily fail since the exception may be an instance instead
- # of a class, in the case of a class exception, or it may be a
- # subclass of the expected exception.)
- bint PyErr_ExceptionMatches(object exc)
- # 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.
- bint PyErr_GivenExceptionMatches(object given, object exc)
- # Return true if the given exception matches the exception 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 exceptions
- # in the tuple (and recursively in subtuples) are searched for a
- # match. If given is NULL, a memory access violation will occur.
- void PyErr_NormalizeException(PyObject** exc, PyObject** val, PyObject** tb)
- # 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.
- void PyErr_Clear()
- # Clear the error indicator. If the error indicator is not set, there is no effect.
- void PyErr_Fetch(PyObject** ptype, PyObject** pvalue, PyObject** ptraceback)
- # Retrieve the error indicator into three variables whose
- # addresses are passed. If the error indicator is not set, set all
- # three variables to NULL. If it is set, it will be cleared and
- # you own a reference to each object retrieved. The value and
- # traceback object may be NULL even when the type object is
- # not. Note: This function is normally only used by code that
- # needs to handle exceptions or by code that needs to save and
- # restore the error indicator temporarily.
- void PyErr_Restore(PyObject* type, PyObject* value, PyObject* traceback)
- # Set the error indicator from the three objects. If the error
- # indicator is already set, it is cleared first. If the objects
- # are NULL, the error indicator is cleared. Do not pass a NULL
- # type and non-NULL value or traceback. The exception type should
- # be a class. Do not pass an invalid exception type or
- # value. (Violating these rules will cause subtle problems later.)
- # This call takes away a reference to each object: you must own a
- # reference to each object before the call and after the call you
- # no longer own these references. (If you don't understand this,
- # don't use this function. I warned you.) Note: This function is
- # normally only used by code that needs to save and restore the
- # error indicator temporarily; use PyErr_Fetch() to save the
- # current exception state.
- void PyErr_SetString(object type, char *message)
- # 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 increment its reference count. The second argument is an
- # error message; it is converted to a string object.
- void PyErr_SetObject(object type, object value)
- # This function is similar to PyErr_SetString() but lets you
- # specify an arbitrary Python object for the ``value'' of the
- # exception.
- PyObject* PyErr_Format(object exception, char *format, ...) except NULL
- # Return value: Always NULL.
- # This function sets the error indicator and returns
- # NULL. exception should be a Python exception (class, not an
- # instance). format should be a string, containing format codes,
- # similar to printf(). The width.precision before a format code is
- # parsed, but the width part is ignored.
- void PyErr_SetNone(object type)
- # This is a shorthand for "PyErr_SetObject(type, Py_None)".
- int PyErr_BadArgument() except 0
- # 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() except NULL
- # Return value: Always NULL.
- # 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(object type) except NULL
- # Return value: Always NULL.
- # 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(object type, object filenameObject) except NULL
- # 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_SetFromErrnoWithFilename(object type, char *filename) except NULL
- # Return value: Always NULL. Similar to PyErr_SetFromErrno(),
- # with the additional behavior that if filename is not NULL, it is
- # passed to the constructor of type as a third parameter. In the
- # case of exceptions such as IOError and OSError, this is used to
- # define the filename attribute of the exception instance.
- PyObject* PyErr_SetFromWindowsErr(int ierr) except NULL
- # Return value: Always NULL. This is a convenience function to
- # raise WindowsError. 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 tuple object whose first item is the ierr value
- # and whose second item is the corresponding error message (gotten
- # from FormatMessage()), and then calls
- # "PyErr_SetObject(PyExc_WindowsError, object)". This function
- # always returns NULL. Availability: Windows.
- PyObject* PyErr_SetExcFromWindowsErr(object type, int ierr) except NULL
- # Return value: Always NULL. Similar to
- # PyErr_SetFromWindowsErr(), with an additional parameter
- # specifying the exception type to be raised. Availability:
- # Windows. New in version 2.3.
- PyObject* PyErr_SetFromWindowsErrWithFilename(int ierr, char *filename) except NULL
- # Return value: Always NULL. Similar to
- # PyErr_SetFromWindowsErr(), with the additional behavior that if
- # filename is not NULL, it is passed to the constructor of
- # WindowsError as a third parameter. Availability: Windows.
- PyObject* PyErr_SetExcFromWindowsErrWithFilename(object type, int ierr, char *filename) except NULL
- # Return value: Always NULL.
- # Similar to PyErr_SetFromWindowsErrWithFilename(), with an
- # additional parameter specifying the exception type to be
- # raised. Availability: Windows.
- void PyErr_BadInternalCall()
- # This is a shorthand for "PyErr_SetString(PyExc_TypeError,
- # 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.
- int PyErr_WarnEx(object category, char *message, int stacklevel) except -1
- # Issue a warning message. The category argument is a warning
- # category (see below) or NULL; the message argument is a message
- # string. stacklevel 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 stacklevel of 1 is the
- # function calling PyErr_WarnEx(), 2 is the function above that,
- # and so forth.
- int PyErr_WarnExplicit(object category, char *message, char *filename, int lineno, char *module, object registry) except -1
- # 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.
- int PyErr_CheckSignals() except -1
- # This function interacts with Python's signal handling. 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. In all cases, the default effect for SIGINT is to raise
- # the KeyboardInterrupt exception. If an exception is raised the
- # error indicator is set and the function returns 1; otherwise the
- # function returns 0. The error indicator may or may not be
- # cleared if it was previously set.
- void PyErr_SetInterrupt() nogil
- # This function simulates the effect of a SIGINT signal arriving
- # -- the next time PyErr_CheckSignals() is called,
- # KeyboardInterrupt will be raised. It may be called without
- # holding the interpreter lock.
- object PyErr_NewException(char *name, object base, object dict)
- # Return value: New reference.
- # This utility function creates and returns a new exception
- # object. The name argument must be the name of the new exception,
- # a C string of the form module.class. The base and dict arguments
- # are normally NULL. This creates a class object derived from
- # Exception (accessible in C as PyExc_Exception).
- void PyErr_WriteUnraisable(object obj)
- # 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. The repr of obj will be printed in the warning
- # message.
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