MPI_SUBARRAYS_SUPPORTED

[jeffhammond]

Set the LOGICAL compile-time constant MPI_SUBARRAYS_SUPPORTED to .TRUE. and declare choice buffers using the Fortran 2008 TS 29113 features assumed-type and assumed-rank, i.e., TYPE(*), DIMENSION(..) in all nonblocking, split collective and persistent communication routines, if the underlying Fortran compiler supports it. With this, noncontiguous sub-arrays can be used as buffers in nonblocking routines.

Rationale. In all blocking routines, i.e., if the choice-buffer is not declared as ASYNCHRONOUS, the TS 29113 feature is not needed for the support of noncontiguous buffers because the compiler can pass the buffer by in-and-out-copy through a contiguous scratch array. (End of rationale.)