Some C-API functions clear the error indicator?

Austin Bingham austin.bingham at
Sat Jan 30 08:17:30 CET 2010

That makes a lot of sense. And if I take the approach that any Py*
function might do this, it actually looks like I can simplify my code
(rather than managing some list of ill-behaved functions or
something.) Thanks!

On Fri, Jan 29, 2010 at 3:58 PM, Duncan Booth
<duncan.booth at invalid.invalid> wrote:
> Austin Bingham <austin.bingham at> wrote:
>> The functions that do this don't seem to indicate in their
>> documentation that this will happen. So first, does anyone know why
>> this is happening? Is it because of the context in which I'm making
>> the calls? Is there any pattern or reason behind which functions will
>> do this? Or am I just doing something wrong?
> (Just guessing here)
> I would expect that any function that executes Python code will clear the
> error.
> I think that has to happen otherwise the Python code will throw an
> exception whenever it gets round to checking for errors. In the past I've
> found that if you fail to check for an error in C code before returning to
> the interpreter you get the exception thrown a few instructions later, so
> something similar would probably happen if you call other Python code from
> C.
> If it is anything that executes Python then that would include any function
> that creates or destroys an object with Python constructor or destructor
> code. or that compares or otherwise operates on instances defined in
> Python. In particular it might mean that any function that doesn't appear
> to clear the error could do so in a slightly different situation.
> --
> Duncan Booth
> --

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