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[mpi-21] F90 bindings



The F90 bindings specified in MPI-2 currently require nearly 7 million interface functions in the Fortran 90 module (!). This large number of interfaces is required because F90 is a strongly-typed language and has no analogue of (void*). MPI_SEND, for example, has to be overloaded with function signatures for every possible type of choice buffer. Worse, many collectives have *2* choice buffers... the end result is that nearly 7M interfaces are needed. As result, many MPI implementations implement only a fraction of the MPI F90 module interface functions.

Additionally, user-defined F90 types cannot be supported.

This is clearly a [big] bug in the F90 bindings. What does the Forum want to do about this for MPI-2.1? Perhaps add some clarification language? Or ...?

Can this issue be added to the discussion list for the bindings subcommittee?

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Jeff Squyres
Cisco Systems