[MPI3 Fortran] MPI Fortran bindings

Jim Xia jimxia at ca.ibm.com
Fri Jun 5 14:43:02 CDT 2009

> > 
> >  > INTENT doesn't help with non-contiguous buffers. 
> > 
> > There is a subtle difference an intent can make: INTENT(IN) will 
> > suppress copy-out if copying has to be made by the compiler.
> Yes, this is a good point in favor of intent.  Similarly, an INTENT(OUT) 

> dummy would suppress a copy-in before the call.

That's not true.  An INTENT(OUT) will not always suppress a copy-in. How 
would you suppress the copy-in of x(::2) at call foo for the following 

module m
    subroutine foo (x)
        real, intent(out) :: x(3)

        x(:) = [1,2,3]
    end subroutine
end module

use m
    real x(10)

    call foo(x(::2))


Jim Xia

XL Fortran Compiler Test
IBM Toronto Lab at 8200 Warden Ave, Markham, On, L6G 1C7
Phone (905) 413-3444  Tie-line 313-3444
email: jimxia at ca.ibm.com
D2/YF7/8200 /MKM

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