Whether or not it is a good idea (and it probably is considered bad practice), I sometimes return an Error in python instead of raising it.
def fnA( some_param ):
# use some_param in complicated thing
if some_param is None:
return ValueError( "something went wrong" )
def fnB( param_a ):
val = fnA( param_a )
if isinstance( val, Exception ):
# error path
I have been trying to create a python C extension from a regular module that I have written both as practice and because I think it could benefit from it. To do that, I have been using pybind11. It covers most of my needs, except that. I cannot seem to create a ValueError and return it from C (or C++ in this case).
I have looked at the documentation, at python's own source code and I have not found a way to create an exception without raising it. What I have "found"/tried is this:
auto some_fn() -> PyExc_ValueError* {
PyObject* type;
PyObject* value;
PyObject* traceback;
PyErr_SetString( PyExc_ValueError, "error in my function !!!" );
PyErr_Fetch( &type, &value, &traceback );
PyErr_NormalizeException( &type, &value, &traceback );
if( traceback != NULL ) {
PyException_SetTraceback( value, traceback );
}
PyErr_Clear();
return value;
}
which sets the exception, fetches it, normalizes it, clears it and returns the concrete error. I thought it would work but it does not even compile.
Anyone can point me in the right direction for creating and returning an exception in the C API? It might not really be possible, but then again, it is so easy in python code, I have a hard time believing it can't be done.
Thanks in any case.
