Hi Robert,

look at static_warning.hpp

My documentation was saying: todo !!!! But I checked the web and found discussion and this lead me to create something useful for me. So I'm sending the info for people interested by the discussion. // This template will NOT produce warning template<typename U, typename V> struct simWarningTypeTruncation { typedef double type; }; // ===================================================================== // char with other // ===================================================================== template<> struct simWarningTypeTruncation<char, float> { typedef char type; }; template<> struct simWarningTypeTruncation<char, double> { typedef char type; }; template<> struct simWarningTypeTruncation<char, long double> { typedef char type; }; // ===================================================================== // short with other // ===================================================================== template<> struct simWarningTypeTruncation<short, float> { typedef short type; }; template<> struct simWarningTypeTruncation<short, double> { typedef short type; }; template<> struct simWarningTypeTruncation<short, long double> { typedef short type; }; // ===================================================================== // int with other // ===================================================================== template<> struct simWarningTypeTruncation<int, float> { typedef int type; }; template<> struct simWarningTypeTruncation<int, double> { typedef int type; }; template<> struct simWarningTypeTruncation<int, long double> { typedef int type; }; // ===================================================================== // long with other // ===================================================================== template<> struct simWarningTypeTruncation<long, float> { typedef long type; }; template<> struct simWarningTypeTruncation<long, double> { typedef long type; }; template<> struct simWarningTypeTruncation<long, long double> { typedef long type; }; #define SIM_STATIC_WARNING_TYPE_TRUNCATION(B, C) \ { \ {simWarningTypeTruncation<B, C>::type x; x = 2.3;} \ } template <typename U, typename V> double fct(U u, V v) { SIM_STATIC_WARNING_TYPE_TRUNCATION(U, V); return u + v; } void main() { std::cout<< fct(1, 2) << std::endl; std::cout<<fct(2, 3.0) << std::endl; std::cout<<fct(3.0, 4) << std::endl; }

Robert Ramey

Remi Ricard wrote:

...

Hi,

I want to warn user about a possible miss use of a function.

Now I'm only able to stop the compilation with the following code

template <typename ValueType> class simVec3 { ......... /// Unary multiply by scalar. /// @param rsh The scalar to multiply the vector with template<class T> simVec3<ValueType>& operator *= (const T& rhs) { // The function should not be use like this // simVec<int> vec(1, 1, 1); // a *= 0.3; // since what a will contain is [0, 0, 0] BOOST_MPL_ASSERT_NOT(( boost::mpl::and_< \ boost::is_floating_point<T>, \ boost::is_integral<ValueType> > ));

ValueType s=static_cast<ValueType>(rhs); vec[0]*=s; vec[1]*=s; vec[2]*=s; return *this; }

What I would want is something like #if A_meta_function_returning_1_if_int_double #pragma message("simVec::Possible type truncation") #endif

instead of the BOOST_MPL_ASSERT_NOT

I also tried something like:

template <bool x> struct AA; template <> struct AA<true> { enum {value = 1 }; }; template <> struct AA<false> { enum {value = 0}; };

template <typename U, typename V> double myfct(U u, V v) { #if ( AA< boost::mpl::and_< boost::is_integral<U>, \ boost::is_floating_point<V> > > ::value ) #pragma message("****** Hellop *********") #endif

return u + v; }

But the compilation is complaining about an unmatched parenthesis

Remi

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