(j3.2006) Question on MOVE_ALLOC

[Bader, Reinhold]

Dear J3,

consider the following program:

module m02
  implicit none
  real, allocatable :: x(:), y(:)
contains
  pure subroutine p(i)
    integer, intent(inout) :: i
    if (i == 1) call move_alloc(x, y)
    i = 2
  end subroutine
end module
program q
  use m02
  implicit none
  integer :: i
  i = 1
  allocate(x(2))
  call p(i)
  if (i==2) then
    write(*,*) 'Computation OK'
  end if
end program

Because MOVE_ALLOC is pure, it can be invoked inside the PURE subroutine. On the other hand it appears
that we have a side effect here, not with respect to the data, but to the allocation status of module variables.
Was it a mistake to make MOVE_ALLOC pure, or is there something missing in the PURE constraint list of chapter
12.7 (16-007r1)?

Cheers
Reinhold

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