Andrey: I am excited to get logging into boost! I may have mentioned this before, but I see logging support for distributed applications as being my essential usecase. For applications distributed by MPI, the interface is MPE: http://www.mcs.anl.gov/research/projects/mpi/www/www4/MPE.html You can see an example here: http://beige.ucs.indiana.edu/I590/node112.html There are a few quirks about this interface, and I wanted to do a sanity check that it was possible to implement as a backend: * You need to have event numbers for different log events. And you need to call an API to get the number: MPE_Log_get_event_number() * There is a way to describe states and their transitions: MPE_Describe_state(.) after you generate them. This allows you to track the duration between state changes... with associated colors. * There is a viewer called "jumpshot" that shows these logs, colors, etc. Anyways, I just wanted to bring this to your attention as an important usecase to think through in the interfaces. And if you happen to write an MPE backend to be packaged with boost::mpi, it would be an amazing addition. -Jesse