A case-insensitive less predicate for strings.
Defined in header
using ci_less = see-below;
The comparison algorithm implements a case-insensitive total order on the set of all ASCII strings; however, it is not a lexicographical comparison. This is a suitable predicate for ordered containers. The function is defined only for strings containing low-ASCII characters.
boost::container::map< std::string, std::string, ci_less > m1; std::map< std::string, std::string, ci_less > m2; // (since C++14)