fortran:fix integer kind=8 problem

[hppritcha]

user reported problem on the ompi-users mail list.

https://www.mail-archive.com/[email protected]//msg35382.html

Signed-off-by: Howard Pritchard [email protected]
(cherry picked from commit 32db65f)

[jsquyres]

@hppritcha Giles noted in 32db65f#commitcomment-154262549 that this might not be right -- the implicit string length argument is passed as an int, not an MPI_Fint.

Can you dig a little deeper and see if this is actually correct?

[janjust]

I'm adding this label until @jsquyres comment is resolved.

[jsquyres]

@hppritcha Is the problem that the result from calling len()

ompi/ompi/mpi/fortran/use-mpi-f08/session_get_nth_pset_f08.F90

Lines 26 to 27 in 674f46c

	call ompi_session_get_nth_pset_f(session%MPI_VAL, MPI_INFO_NULL%MPI_VAL, n, &
	pset_len, pset_name, c_ierror, len(pset_name))

is an 8 byte integer (e.g., someone compiled with fortran -i8), but the C int is only 4 bytes?

If so, that sounds like a correct compiler error to me. Can we cast the return of the len() down to 4 bytes or something? If someone is passing a string that is longer than 2^31 bytes long, we have other problems. 😄

[jsquyres]

@hppritcha Is the problem that the result from calling len()

Actually, have a look at what @ggouaillardet posted on the original PR to main: #13159 (comment)

[hppritcha]

I was following how ompi_comm_get_name_f etc were handling this.