Passing arrays as pointers

[marrisa]

Dear members,

I am currently passing an allocatable array into a function however I am getting a multitude of warnings. I think the solution is to pass the array into the function as a pointer ghowever I have no experience with this matter. I would be greatful if someone could show me how this is done..

Thank you in advance
marrisa

 

[xwb]

Could you paste a sample of your code which is giving all these warnings.

Here is an example of using allocate/deallocate

module ARayOfHope
contains
subroutine fillarr (arr, arrmax)
   ! Size of array unknown to compiler
   integer, intent(inout)::arr(:)
   integer, intent(in)::arrmax
   integer:: i
   do i = 1, arrmax, 1
      arr(i) = i * i
   enddo

   return
end subroutine

subroutine dumparr (arr, arrmax)
   ! Size of array unknown to compiler
   integer, intent(in)::arr(:)
   integer, intent(in)::arrmax
   integer:: i
   do i = 1, arrmax, 1
      print *, arr(i)
   enddo
   return
end subroutine
end module

module BlockData
   ! Declare an allocatable array
   integer, dimension(:), allocatable :: dyn
   integer::dynmax
   parameter (dynmax = 10)
end module

program main
   use ARayOfHope
   use BlockData
   integer::i
   !
   ! allocate space
   allocate (dyn(dynmax))
   !
   ! do something with the array
   call fillarr (dyn, dynmax)
   call dumparr (dyn, dynmax)
   !
   ! deallocate the space
   deallocate (dyn)
   stop
end program

 

[xwb]

Example of pointer usage

program main
   integer, pointer:: iptr(:)
   integer:: saymax
   parameter (saymax = 10)
   integer, target:: say(saymax)
   integer:: i

   ! Fill an array
   do i = 1, saymax, 1
      say(i) = i * i
   enddo

   ! Pointer is from element 2:saymax - 1
   iptr => say(2:saymax - 1)
   ! Use the pointer like any array
   do i = 1, saymax - 2, 1
      print *, i, ' = ', iptr(i)
   enddo
   stop
end program

[/CODE]

 

[marrisa]

The subroutine is very long however it is of the following form....

subroutine GenData(num)

external function1

integer num
real, allocatable :: Array1), Array2)

allocate(Array1(num))

Array2 = function1(Array1, num)

end subroutine

I didnt need to use a pointer after all, the porblem was that I wasnt using an explicit interface in the subroutine...A call to a routine which returns an array, or which has a deferred-shape array argument MUST have an explicit interface visible to the caller...

Thanks xwb for your help...