[C++-sig] howto check for an attr from c++?

[Neal Becker]

Stefan Seefeld wrote:

> Neal Becker wrote:
>> I need to check if an object has an attribute from c++.
>> 
>> I'm using this low-level approach:
>> (r is an object):
>>     if (PyObject_HasAttrString (r.ptr(), "__len__")) {
>> 
>> Nothing wrong with that, but is there something in the boost::python api
>> to handle this?
> 
> boost::python does provide getattr(), setattr(), and delattr().
> 
> HTH,
> Stefan
> 

If I call getattr() on a nonexistent attribute, what happens?  Does python
throw an exception?  (I believe it does). If so, how do I intercept it from
c++?  I'm trying to test is an attribute is defined.