[Boost-users] boost::multi_index

Hello, I have a question regarding creating composite key/specifying length for arrays while using multi_index container based on following structure. struct TestStruct { char firstKey[50]; char secondKeyPart[3]; uint32_t thirdKeyPart; ......Some other information.... }; Do I really read to specify this lengths for character arrays? If yes, how do I do that while specifying key parts as below? typedef multi_index_container < TestStruct, indexed_by< //non-unique as some subscribers might have more than one number hashed_unique< composite_key< TestStruct, member, member, member, > >

TS;

Thanks