PROGRAM array
 IMPLICIT NONE
 REAL, ALLOCATABLE, DIMENSION(:,:) ::a
 REAL :: res
 INTEGER ::n1,n2
 
 INTERFACE
  SUBROUTINE sub(b,res)
   REAL,INTENT(OUT) :: res
   REAL, DIMENSION (:,:),INTENT(IN)::b
   REAL,DIMENSION (SIZE(b,1),SIZE(b,2)) :: work
  END SUBROUTINE sub
 END INTERFACE
 
 WRITE(*,*) "n1, n2?"
 READ (*,*) n1,n2
 ALLOCATE(a(n1,n2))
 CALL sub(a,res)
 WRITE(*,*) "Size(A) = ", res
END PROGRAM array

   SUBROUTINE sub(b,res) !la subroutine è esterna
     IMPLICIT NONE
     REAL,INTENT(OUT) :: res
     REAL, DIMENSION (:,:),INTENT(IN)::b
     REAL,DIMENSION (SIZE(b,1),SIZE(b,2)) :: work
     
	WRITE(*,*) 'Bounds and size of work: ', &
			&	LBOUND(work), UBOUND(work), SIZE(work)
    res=SIZE(b)
   END SUBROUTINE sub