Re: Assumed-shape arrays and dummy procedures

On Apr 6, 3:56 am, "James Van Buskirk" <not_va...@xxxxxxxxxxx> wrote:
      subroutine callthru(qsub, option)
         implicit logical(q)
         integer, intent(in) :: option
         external qsub

         if(option == 1) then
            write(*,'(a)') 'Calling subroutine A'
            call A(qsub, 2)

"A" takes a subroutine as argument.

         else if(option == 2) then
            write(*,'(a)') 'Calling subroutine B'
            call B(qsub, 2)

While "B" takes a function as argument.

I believe the program is invalid. Quoting the Fortran 2003 standard:

"12.4.1.3 Actual arguments associated with dummy procedure entities"
[...]
"If the interface of the dummy argument is implicit and either the
name of the
dummy argument is explicitly typed or it is referenced as a function,
the dummy
argument shall not be referenced as a subroutine"

As you once reference "qsub" as function and once as subroutine (by
using them as actual argument), the program is invalid and the
compiler is free to reject it. Interestingly, most compiler accept a
reduced version which contains such calls. For the most reduced
version which uses implicit typing, of my compilers, only gfortran
rejects it. For the full program, most of my compilers reject it.

In conclusion, I think gfortran is right and your program is invalid.


      subroutine  A(sub, n)
         integer, intent(in) :: n
         interface
            subroutine sub(x)
               implicit none
               real, intent(in) :: x(:)
            end subroutine sub
         end interface

      subroutine B(sub, n)
         integer, intent(in) :: n
         interface
            function sub(x)
               implicit none
               integer, intent(in) :: x
               logical sub(x)
            end function sub
         end interface

Tobias
.

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