C++ Logging api -

which efficient, configurable , portable c++ diagnostic logging api/ library.

i working on multi threaded application multiple sub components.

• i should able enable/disable logging desired sub system needed should support logging severity within sub component.
• the api/library should write logging temporary storage (circular buffer) , save file on user request.
• most importantly have overloaded operator able print objects

take @ pantheios , boost.log.