Extract the return type of a function without calling it (using templates?)

Question

I\'m looking for a way in C++ to extract the return type of a function (without calling it). I presume this will require some template magic.

float Foo();
i         


        

Answer 1

It's tricky because function names are expression not types - you need something like gcc's typeof. Boost's TypeOf is a portable solution that gets very close.

However, if the code can be organised so that the work is done inside a function template to which Foo or Bar can be passed, there's a straight-forward answer:

template 
void test(R (*)())
{
  R var1;
}

int main()
{
  test(&Foo);
}