On Fri, Apr 13, 2012 at 8:02 AM, John M. Dlugosz <mpbecey7gu@snkmail.com> wrote:
I'm using Visual Studio 10, and Boost 1.49. The following complete CPP file compiles without error:
I don't have access to VS 10 so...bear with me...
=====
#include <boost/test/unit_test.hpp>
#include "boost/thread/future.hpp"
#include <boost/utility/result_of.hpp>
#include <functional>
using boost::unique_future;
template <typename F>
unique_future<typename boost::result_of< F() >::type>
foo (F&& f)
{
typedef typename boost::result_of< F() >::type RetType;
unique_future<RetType> future_result;
return std::move(future_result);
}
template <typename F, typename A1>
unique_future<typename boost::result_of< F(A1) >::type>
foo (F&& f, A1&& a1)
{
return std::move(foo (std::tr1::bind(f,a1)));
}
class C {};
class D : public C {
public:
void mf() const { }
// virtual void toxic() { }
};
void mainfunc()
{
D* p;
foo (&D::mf, p);
}
=====
But, if you un-comment the definition of toxic, then it will not compile, giving instead:
1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2825: 'F': must be a class or namespace when followed by '::'
1> E:\boost_1_49\boost/utility/result_of.hpp(90) : see reference to class template instantiation 'boost::detail::result_of_nested_result<F,FArgs>' being compiled
1> with
1> [
1> F=void (__thiscall D::* &)(void) const,
Hmmm...I wonder if the problem is that F is bound to a *reference* to a pointer-to-member. Although then I'm surprised things work without the base class or the virtual member function.
Try replacing "F" in your boost::result_of queries with boost::remove_reference<F>::type.
1> FArgs=void (__thiscall D::* &(D *&))(void) const
1> ]
1> E:\boost_1_49\boost/utility/detail/result_of_iterate.hpp(33) : see reference to class template instantiation 'boost::detail::tr1_result_of_impl<F,FArgs,HasResultType>' being compiled
1> with
1> [
1> F=void (__thiscall D::* &)(void) const,
1> FArgs=void (__thiscall D::* &(D *&))(void) const,
1> HasResultType=false
1> ]
Also, see if changing line 25 in result_of_iterate.hpp (near the reference above) to
mpl::or_< is_pointer< typename boost::remove_reference<F>::type >, is_member_function_pointer< typename boost::remove_reference<F>::type > >
from
mpl::or_< is_pointer<F>, is_member_function_pointer<F> >
helps.
1> E:\boost_1_49\boost/utility/detail/result_of_iterate.hpp(75) : see reference to class template instantiation 'boost::tr1_result_of<F>' being compiled
1> with
1> [
1> F=void (__thiscall D::* &(D *&))(void) const
1> ]
1> threadpoolTest.cpp(39) : see reference to class template instantiation 'boost::result_of<F>' being compiled
1> with
1> [
1> F=void (__thiscall D::* &(D *&))(void) const
1> ]
1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2516: 'F' : is not a legal base class
1> E:\boost_1_49\boost/utility/result_of.hpp(90) : see declaration of 'F'
1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2143: syntax error : missing ',' before '::'
1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2903: 'result' : symbol is neither a class template nor a function template
1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2039: 'result' : is not a member of '`global namespace''
1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2504: 'result' : base class undefined
1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2143: syntax error : missing ',' before '<'
1>threadpoolTest.cpp(39): error C2893: Failed to specialize function template 'boost::unique_future<boost::result_of<F(T0)>::type> foo(F &&,A1 &&)'
1> With the following template arguments:
1> 'void (__thiscall D::* &)(void) const'
1> 'D *&'
1>threadpoolTest.cpp(39): error C2780: 'boost::unique_future<boost::result_of<F(void)>::type> foo(F &&)' : expects 1 arguments - 2 provided
1> threadpoolTest.cpp(10) : see declaration of 'foo'
1>
1>Build FAILED.
Note that both the presence of a virtual function and a base class in necessary. if toxic is present but C is not, then it still works.
Again, this seems mysterious to me...
- Jeff