I will need to check if the fortran and c++ codes have the NC_DISKLESS flag defined. If they do, and you use it, then they will use the underlying NC_DISKLESS mechanism in the c library. But note that NC_DISKLESS is not always the right thing to use. It provides performance improvements only in specific situations. =Dennis Heimbigner Unidata Ticket Details =================== Ticket ID: UOQ-618039 Department: Support netCDF Priority: Normal Status: Closed