Using a hashmap

with BOOST

• unordered

with GCC

A header to use the hash_map<Key,Type> (same member functions/objects as a std::map<Key,Type>) which is not in the stl library: <source lang="cpp">

1. ifdef __GNUC__

       #if __GNUC__ < 3
               #include <hash_map>
       #else
               #include <ext/hash_map>
               #if __GNUC_MINOR__ == 0
                       using namespace std;       // GCC 3.0                                                                                          
               #else
                       using namespace __gnu_cxx; // GCC >= 3.1                                                                                  
               #endif
       #endif

1. endif

</source>

Ref : From Gnu Compiler Collection Internals