Re: Is this standard c++...

On 28 Feb, 01:25, "kwikius" <a...@servocomm.freeserve.co.uk> wrote:


Well I was wrong about that :.
(Back to the drawing board I guess)

 But at least the code seems to detect the problem :

#include <stdexcept>

// aka std::tr1::
template <typename T>
struct alignment_of{
   #if defined _MSC_VER
      static const unsigned int value = __alignof (T);
   #elif defined __GNUC__
      static const unsigned int value = __alignof__(T);
   #else
   #error need to define system dependent align_of
   #endif
};

template<typename T, size_t T_sz>
class lmem {

  unsigned char m_buf[T_sz];
public:
  void* loadptr() {
// check its aligned correctly
    ptrdiff_t dummy = m_buf - static_cast<unsigned char*>(0);
    ptrdiff_t offset = dummy % alignment_of<T>::value;
   if(!offset)
      return m_buf;
      throw std::logic_error("lmem memory doesnt staisfy alignment");
  }
};

#include <iostream>
int main()
{
   try{
   typedef double type;
   char c;
   lmem<type,sizeof(type)> x;
   void * p = x.loadptr() ;
   }
   catch(std::exception & e)
   {
      std::cout << e.what() <<'\n';
   }
}
/* output:
lmem memory doesnt staisfy alignment

*/
regards
Andy Little