On 12/9/2010 5:35 AM, Anthony Williams wrote:
Edward Diener<eldiener@tropicsoft.com> writes:
I will continue to look for a workaround for VC9 and earlier, as I think my library should be usable by VC9, VC8, and perhaps VC7.1. Thanks for your neat solution for VC10 !
The following works with VC8, VC10 and g++ 4.4. It causes an Internal Compiler Error with VC7.1 though :-(
Thanks, Anthony ! Works with VC9 also. I will play around more with VC7.1 but I will not worry if I can not get it to work there as that is a pretty old version of VC now. My original code works with gcc 4+ so gcc is not an issue.
#include<iostream>
typedef char small_type;
struct large_type { small_type dummy[2]; };
template<bool,typename T> struct enable_if;
template<typename T> struct enable_if<true,T> { typedef T type; };
template<typename T,typename DT> struct has_member_cMem_of_type { template<typename U> static small_type check2(DT (U::*)); template<typename U> static large_type check2(U);
template<typename U> static typename enable_if< sizeof(check2(&U::cMem))==sizeof(small_type), small_type>::type has_matching_member(int); template<typename U> static large_type has_matching_member(...);
static const bool value=sizeof(has_matching_member<T>(0))==sizeof(small_type); };
struct Gipf { };
struct Dvonn { Gipf cMem; };
struct Tzaar { int cMem; };
struct Yinsh { int Zertz; void cMem(); };
struct Derived: Dvonn {};
int main() { std::cout<<"one:"<<has_member_cMem_of_type<Dvonn, Gipf>::value<<std::endl;
std::cout<<"two" ":"<<!has_member_cMem_of_type<Dvonn, int>::value<<std::endl;
std::cout<<"three" ":"<<!has_member_cMem_of_type<Tzaar, Gipf>::value<<std::endl; std::cout<<"four" ":"<< has_member_cMem_of_type<Tzaar, int>::value<<std::endl;
std::cout<<"five" ":"<<!has_member_cMem_of_type<Yinsh, Gipf>::value<<std::endl; std::cout<<"six" ":"<<!has_member_cMem_of_type<Yinsh, int>::value<<std::endl;
std::cout<<"seven" ":"<<has_member_cMem_of_type<Derived, Gipf>::value<<std::endl; std::cout<<"eight" ":"<<!has_member_cMem_of_type<Derived, int>::value<<std::endl; }
Anthony