[C++-sig] Re: boost::python::object and stl::map warning

[David Abrahams]

Cedric Shock wrote:

> To whomever can provide some assistance:

> It compiles with g++ 3.2.2, and will work as expected in python. 
> However, for each of those offending statements it produces a warning like:
> 
> (data.count(oi)):
> warning: cannot pass objects of non-POD type `struct 
> std::_Rb_tree_iterator<std::pair<const boost::python::api::object, 
> boost::python::api::object>, const std::pair<const 
> boost::python::api::object, boost::python::api::object>&, const 
> std::pair<const boost::python::api::object, 
> boost::python::api::object>*>' through `...'; call will abort at runtime
> 
> (data[oi].ptr()):
> warning: cannot pass objects of non-POD type `struct 
> std::_Rb_tree_iterator<std::pair<const boost::python::api::object, 
> boost::python::api::object>, std::pair<const boost::python::api::object, 
> boost::python::api::object>&, std::pair<const 
> boost::python::api::object, boost::python::api::object>*>' through 
> `...'; call will abort at runtime
> 
> 
> This warning usually indicates that something bad has been done with a 
> variable argument function like passing a non-POD type to printf. But it 
> should not be an issue here. std::map is routinely used to deal with 
> non-POD objects, why can't it handle the boost::python::object?

Short answer:  it can.

Long answer: The warning is benign, since the function "invocation" is 
inside sizeof(...) and never actually happens.  The compiler should be 
smarter about this.

Even longer answer:  Turn off the warning; it'll cause problems with 
other parts of Boost.

Still longer answer:  Ok, ok.  Try the enclosed patch ;->

HTH,
Dave
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