Page 339 lines 21-24 of MPI-2.2 states the following: "It is erroneous to have concurrent confl icting accesses to the same memory location in a window; if a location is updated by a put or accumulate operation, then this location cannot be accessed by a load or another RMA operation until the updating operation has completed at the target." What does this mean when I do PUT with a datatype with overlapping buffers? Is that valid or erroneous? -- Pavan -- Pavan Balaji http://www.mcs.anl.gov/~balaji