[Boost-users] a difference of boost.function between g++4.13 and vc8

I wrote some code using boost.function. Compiling it both in g++4.13 and vc8, I find that I can not declare a struct in function with operator() and use boost.function to call it when I use g++. Just like this: int main() { struct int_div { float operator()(int x, int y) const { return ((float)x)/y; }; }; boost::function f = int_div(); std::cout << f(5, 3) << std::endl; return 0; } When I compile the code above in g++, it give me the error : 请求从 'main()::int_div' 转换到非标量类型 'boost::function'(I use ubuntu chinese.) but when I move the int_div definition outside of main(), It is ok! And the code above VC8 can compile it! why?