On Jun 7, 2004, at 7:11 PM, Hurd, Matthew wrote:
SFINAE does not kick in, because the condition (is_arithmetic<std::string>::value) is not dependent on any template arguments. Cheers, Jaakko
template< bool > typename boost::enable_if_c< boost::is_arithmetic<std::string>::value, void >::type exchange_code( boost::call_traits<std::string>::param_type new_exchange_code ) { lock lk(guard_ ); exchange_code<false>( new_exchange_code); }
template< bool > typename boost::disable_if_c< boost::is_arithmetic<std::string>::value , void >::type exchange_code( boost::call_traits<std::string>::param_type new_exchange_code ) { exchange_code<false>( new_exchange_code); }
Forget the relevance of the is_arithmetic bit, I use my own needs_lock thingo.
For a start:
The compiler correctly identifies that ::type is not a member, but SFINAE does not seem to kick in if I'm reading it correctly. ____________________ c:\source\matt\trading_engine\controller\instrument.hpp(66) : error C2039: 'type' : is not a member of 'boost::enable_if_c<B,T>' with [ B=false, T=void ] c:\source\matt\trading_engine\controller\instrument.hpp(143) : see reference to class template instantiation 'te::instrument<S>' being compiled ____________________
template< bool > typename boost::disable_if_c< boost::is_arithmetic<std::string>::value , void >::type exchange_code( boost::call_traits<std::string>::param_type new_exchange_code ) { exchange_code<false>( new_exchange_code); }
Is fine...
Flipping the conditions round by changing to is_arithmetic< int > flips the failures around.
Same issue with the extra parameter approach:
template< bool > void exchange_code( boost::call_traits<std::string>::param_type new_exchange_code, typename boost::enable_if_c< boost::is_arithmetic<int>::value, void
::type* dummy = 0 ) { lock lk(guard_ ); exchange_code<false>( new_exchange_code); }
template< bool > void exchange_code( boost::call_traits<std::string>::param_type new_exchange_code, typename boost::disable_if_c< boost::is_arithmetic<int>::value , void >::type* dummy = 0 ) { exchange_code<false>( new_exchange_code); }
Is SFINAE meant to work in this way with member templates with enable_if, vc7.1 and boost 1.31?
Something simple is probably escaping me...
Any thoughts?
Regards,
Matt Hurd. _______________
Matt Hurd +61.2.8226.5029 hurdm@sig.com Susquehanna _______________
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