I am having a problem with Boost.Bind (1.33.1). Consider the following simplified code:
struct Bob {
void func() { }
};
void bob_test() {
typedef std::map BobMap;
BobMap bob_map;
std::for_each(bob_map.begin(), bob_map.end(),
bind(&Bob::func, bind(&BobMap::value_type::second, _1)));
}
This fails to compile under DevStudio 8. The problem is the outer bound functor expects (Bob* const) but is passed (Bob const*).
This seems a straight forward use -- call the "func" method on every Bob instance in the map. I can get this to compile if I change the inner bind to "bind(...)". Shouldn't the default return type of the binding of (R T::*) be (R&)? I looked through the bind and mem_fn documentation and didn't see any mention of that. The .* operator applied to a non-const T and a (R T::*) returns (R&), so it is implied that mem_fn of a data member does as well.
Also, why does the error message refer to pointers and not references? Is that an artifact of compiler argument matching failure?
Exact message:
1>inc\boost/bind/mem_fn_template.hpp(31) : error C2440: 'argument' : cannot convert from 'const Bob *' to 'Bob *const '
1> inc\boost/bind/mem_fn_template.hpp(56) : see reference to function template instantiation 'R boost::_mfi::mf0::call<const U>(U &,const T *) const' being compiled
1> with
1> [
1> R=void,
1> T=Bob,
1> U=Bob
1> ]
