Re: [Boost-users] Insertion/Use of boost::multi_index

El 19/09/2016 a las 7:54, Ram escribió:

Hi All ,

I have created a boost::multi_index container for my use and it compiles successfully. [...] The container I defined is ,

typedef boost::multi_index_ClassX< ClassX*, boost::multi_index::indexed_by< boost::multi_index::hashed_unique< boost::multi_index::const_mem_fun, boost::multi_index::const_mem_fun,

...

MultiIndexedClassX;

I'm afraid this is seriously wrong (leaving aside the translation typos such as "boost::multi_index_ClassX" instead of "boost::multi_index_container" etc.) The structure of a definition of a multi_index_container is multi_index_container< element_type, indexed_by< index_specifier1<index1 args>, index_specifier2<index2 args>, ... >

where each index_specifier is one of "hashed_unique", "hashed_non_unique", "ordered_unique", etc. I assume your intention is to have *two* hashed indices (by key1 and key2, respectively), so rather than indexed_by< hashed_unique

(which is what you've written), the definition has to follow this structure: indexed_by< hashed_unique, hashed_unique

See the difference? Your original definition is just plain wrong, and the fact that it seems to compile is sheer luck (or lack of it): once you start trying to use it, compile-time errors will pop up. (if you're curious, Boost.MultiIndex is trying to use your second const_mem_fun as a hash function of the first const_mem_fun, which, of course, makes no sense, but this is what you instructed the lib to do). I've written a small test program reproducing your scenario that you can play with at http://coliru.stacked-crooked.com/a/456f8546e51a29e6 Note that, here, sample.insert(&a) works without problems. Joaquín M López Muñoz