boost::tokenizer_detail::traits_extension does not expose correctly std::_Secure_char_traits_tag on VC9

[emilm@…]

This issues warning C4996: 'std::char_traits<char>::[various] ': Function call with parameters that may be unsafe because VC STL relies on a tag to chose the safe/unsafe version of the function.

 typedef std::basic_string<char>::traits_type Tr;
 typedef boost::tokenizer_detail::traits_extension<Tr> Traits;
 cout << typeid(std::_Char_traits_category_helper<Tr,true>::_Secure_char_traits).name() << endl;
 cout << typeid(std::_Char_traits_category_helper<Traits,true>::_Secure_char_traits).name() << endl;

prints

 _Secure_char_traits_tag
 _Unsecure_char_traits_tag

because _Char_traits_category_helper is defined as

template <class _Traits>
class _Char_traits_category_helper<_Traits, true>
 {
  public:
  typedef typename _Traits::_Secure_char_traits _Secure_char_traits;
 };

so it defers to a typedef of _Secure_char_traits inside the trait. By default it is defined to _Unsecure_char_traits_tag.

This affects builds with /WX (treat warnings as errors) and generally causes a lot of warnings for otherwise harmless code (for example date_time relies on tokenizer to parse strings)

[emilm@…]

A possible fix would be to add this in the definition of traits_extension ( token_functions.hpp line 215 for boost 1_44)

#if defined(BOOST_MSVC) && defined(_SECURE_SCL)
 typedef typename std::_Char_traits_category<traits>::_Secure_char_traits _Secure_char_traits;
#endif