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If I do (e.g.)
open("/snafu/fnord")
in Python (and the file does not exist), I get a traceback and the message
IOError: [Errno 2] No such file or directory: '/snafu/fnord'
I would like to get the above string with Python's C API (i.e., a Python interpreter embedded in a C program). I need it as a string, not output to the console.
With PyErr_Fetch() I can get the type object of the exception and the value. For the above example, the value is a tuple:
(2, 'No such file or directory', '/snafu/fnord')
Is there an easy way from the information I get from PyErr_Fetch() to the string the Python interpreter shows? (One that does not involve to construct such strings for each exception type yourself.)
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To catch and print an exception that occurred in a code snippet, wrap it in an indented try block, followed by the command "except Exception as e" that catches the exception and saves its error message in string variable e . You can now print the error message with "print(e)" or use it for further processing.
The BaseException is the base class of all other exceptions. User defined classes cannot be directly derived from this class, to derive user defied class, we need to use Exception class. The Python Exception Hierarchy is like below.
To chain exceptions, use the raise from statement instead of a simple raise statement. This will give you information about both errors. except ValueError as e: raise RuntimeError( 'A parsing error occurred' ) from e...
In contrast, the except Exception as e statement is a statement that defines an argument to the except statement. e in the latter statement is utilized to create an instance of the given Exception in the code and makes all of the attributes of the given Exception object accessible to the user.31-Dec-2021.
I think that Python exceptions are printed by running "str()" on the exception instance, which will return the formatted string you're interested in. You can get this from C by calling the PyObject_Str() method described here:
https://docs.python.org/c-api/object.html
Good luck!
Update: I'm a bit confused why the second element being returned to you by PyErr_Fetch() is a string. My guess is that you are receiving an "unnormalized exception" and need to call PyErr_NormalizeException() to turn that tuple into a "real" Exception that can format itself as a string like you want it to.
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