I can't find these in the MPICH test suite or anywhere else on the internet, except in contexts where they are included because they are part of the MPI API. These functions have been in MPI since 2.1, i.e. 2008. If there is no usage after 15 years, we should deprecate these functions. As best I can tell, they are nontrivial to implement, so their existence is a distraction for anyone wishing to apply their creative energy to MPI I/O. Jeff -- Jeff Hammond [email protected] http://jeffhammond.github.io/