Re: [boost] [result_of] ambiguous instantiation for function pointers

From: Eric Niebler (eric_at_[hidden])
Date: 2007-03-04 22:21:18

shunsuke wrote:
> Hi,
> 
> CVS HEAD can't compile this under maybe any conforming compiler.
> (RC_1_34 is ok.)
> 
> 
> 	#include <boost/utility/result_of.hpp>
> 
> 	int my_fun(int) { return 0; }
> 
> 	template< class F >
> 	void test(F )
> 	{
> 	    typedef typename
> 	        boost::result_of<F()>::type
> 	    result_t; // shall be 'void'.
> 	}
> 
> 	int main()
> 	{
> 	    ::test(&my_fun);
> 	}
> 
> 
> Specializations are not enough?

I'm a bit confused. The type of F is int(*)(int). You're asking what the 
return type is if you call it with no parameters. But you can't do that! 
It takes an int. result_of<F(int)>::type compiles fine. I'm not sure 
this is a bug. Can you justify why you think this code should compile?

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com