On Thu, May 1, 2008 at 6:07 PM, Hicham Mouline <hicham@mouline.org> wrote:

Thanks for your clarifications,

In your example, if "MyFunc" was typedef'd before its use in the template argument as say

typedef int (*MyFunc)(int);
it would not conflict with its use in the template argument ?

First of all. I am sorry for an error I made when stated:

template<T MyFunc()>
struct X
{
   typedef T             result_type;
   typedef MyFunc   function_type;
};

This is not a valid C++ code, since MyFunc as the template parameter is a real pointer to a function, it is not a type. And you cannot make a typedef for a pointer. Only for it's type.

To visualize the usage I have written a small program:

#include <iostream>
#include <typeinfo>

typedef int (*MyFunc)(int, int);

int get_int(int x)
{
    return x;
}

int plus(int x, int y)
{
    return x+y;
}

template<int (*MyFunc)(int)>
struct X
{
typedef int           result_type;

result_type exec()const
{
    ::MyFunc f2 = + //use scope resolution to access the global MyFunc
    return MyFunc(10)+f2(10,10);
}
};

int main(int argc, char* argv[])
{
    X<&get_int>    x;
    std::cout << "sum: " << x.exec() << "\n";
}

best regards,