On Tue, Mar 29, 2011 at 11:51 AM, Michael Kaes <michael.kaes@gmail.com>wrote:
Hi all,
I am playing around with enable_if and I want to create a constructor switch. The code is the following:
------------------------------------------------ struct NullType{}; struct TestType{}; struct NonNull{};
template<typename T, typename U = NullType> struct TemplateStruct { TemplateStruct(int i, typename boost::enable_if<boost::is_same<U, NullType>, void* >::type dummy = 0) { std::cout << "One Param == " << i << std::endl; }
TemplateStruct(int i, int j, typename boost::disable_if<boost::is_same<U, NullType>, void* >::type dummy = 0) { std::cout << "Two Param == " << i << "," << j << std::endl; } };
int main(int /*argc*/, char**) { TemplateStruct<TestType>(1); TemplateStruct<TestType,NonNull>(1,2); return 0; } -------------------------------------
I want that the first Ctor is only available when a NullType is passed in and if not that the second one is available but not the first. I don't want to do a class specialization because the class is rather big and extracting all the methods to a common class would be difficult. So how can I reuse the template parameter U for the Ctors enable_if? Or is this simply not possible?
Regards, Michael
Hi! Here is the answer to your question. I had a similar problem. http://lists.boost.org/boost-users/2007/11/31849.php <http://lists.boost.org/boost-users/2007/11/31849.php>With Kind Regards, Ovanes