Consider a template class like: template<typename ReturnType, ReturnType Fn()> class Proxy { void run() { ReturnType ret = Fn(); // ... do something ... } }; // and a functions int fn1() { return 5; } float fn2() { return 5; } This can be instantiated by using: Proxy<int, &fn1> p1; But explicitly declaring th...
I'm trying to learn the currently accepted features of c++0x and I'm having trouble with auto and decltype. As a learning exercise I'm extending the std class list with some generic functions. template<class _Ty, class _Ax = allocator<_Ty>> class FList : public std::list<_Ty, _Ax> { public: void iter(const function<void (_Ty)>& f) ...
I'm trying to use C++0x, and in particular lambda expression and decltype to simplify some of my code, using the MSVC10 RC compiler. I've run into the following very odd problem: template <typename F> auto foo(F f) -> decltype(f()){ return f(); } template <typename F> void bar(F f){ f(); } int main() { bar([](){ foo([]() { ...
I have some trouble understanding the need for std::result_of in C++0x. If I understood correctly, result_of is used to obtain the resulting type of invoking a function object with certain types of parameters. For example: template <typename F, typename Arg> typename std::result_of<F(Arg)>::type invoke(F f, Arg a) { return f(a); } ...
I don't understand the last line of the example on page 148 of the FCD (§7.6.1.2/4): const int&& foo(); int i; struct A { double x; }; const A* a = new A(); decltype(foo()) x1 = i; // type is const int&& decltype(i) x2; // type is int decltype(a->x) x3; // type is double decltype((a->x)) x4 = x3; // type is co...
I'm writing some code to translate a C++ type to an appropriate type for a SQL DB. I want to identify the type, and then depending on what it is, produce the appropriate SQL code. I'm not sure exactly what can be done in this regard by using RTTI, auto, or decltype. I have some ideas but I'm not sure if they're workable. For instance...