lundi 30 mai 2016

alias for multi parameter function template

I am trying to create a template for a multi-parameter function, and then an alias for a particular instantiation. From this really good post:

C++11: How to alias a function?

I found example code that works for a single function parameter and single template parameter:

#include <iostream>
namespace Bar
{
   void test()
   {
      std::cout << "Test\n";
   }

   template<typename T>
   void test2(T const& a)
   {
      std::cout << "Test: " << a << std::endl;
   }
}

void (&alias)()        = Bar::test;
void (&a2)(int const&) = Bar::test2<int>;

int main()
{
    Bar::test();
    alias();
    a2(3);
}

When I try to expand to two function parameters as such:

void noBarTest(T const& a, T const& b)
{
    std::cout << "noBarTest: " << a << std::endl;
}

void(&hh)(int const&, int const&) = noBarTest<int, int>;

I get these errors in Visual Studio:

error C2440: 'initializing' : cannot convert from 'void (__cdecl *)(const T &,const T &)' to 'void (__cdecl &)(const int &,const int &)'

IntelliSense: a reference of type "void (&)(const int &, const int &)" (not const-qualified) cannot be initialized with a value of type ""

I thought I followed the pattern exactly in expanding to 2 arguments.
What's the proper syntax for this?

Aucun commentaire:

Enregistrer un commentaire