N.M. Maclaren wrote:

While this is true, a reasonable alternative approach (which is what is actually done by must current implementations for MPI handles) is to use an integer token in Fortran, and have the using routines decode it. Sure, if you want to stay with the dark ages, go ahead. I don't find it alternative to force people to write tables for encoding and decoding pointers in a 64 bit integer. It is called a virtual memory system and is already done by the operating system. For a language that supports pointers, there is no reason to hack integers (that is a good idea in scientific codes for efficiency and other considerations, but not here). Best, Aleks