anchor.diff:    integer(I4P),                     intent(INOUT):: cf         !< Current file index (for concurrent files IO).
     integer(I4P),                     intent(INOUT):: Nvtk       !< Number of (concurrent) VTK files.
     type(Type_VTK_File), allocatable, intent(INOUT):: vtk(:)     !< VTK files data.
  -  type(Type_VTK_File), allocatable::                vtk_tmp(:) !< Temporary array of VTK files data.
  -  !---------------------------------------------------------------------------------------------------------------------------------
  -
  -  !---------------------------------------------------------------------------------------------------------------------------------
  -  select case(Upper_Case(trim(act)))
  +  type(Type_VTK_File), allocatable               :: vtk_tmp(:) !< Temporary array of VTK files data.
  +  character(len=len(act))                        :: upper_act !< Converted string.
  +  !---------------------------------------------------------------------------------------------------------------------------------
  +
  +  !---------------------------------------------------------------------------------------------------------------------------------
  +! XLF error: 1511-051 (S) The type of the SELECT CASE expression is invalid.
  +  upper_act = Upper_Case(trim(act))
  +  select case(upper_act)
     case('ADD')
       if (Nvtk>0_I4P) then
         allocate(vtk_tmp(1:Nvtk))
  
positive.code:   !---------------------------------------------------------------------------------------------------------------------------------
    endsubroutine byte_update
  
    pure subroutine vtk_update(act,cf,Nvtk,vtk)
    !---------------------------------------------------------------------------------------------------------------------------------
    !< Subroutine for updating (adding and removing elements into) vtk array.
    !---------------------------------------------------------------------------------------------------------------------------------
  
negative.code:   !---------------------------------------------------------------------------------------------------------------------------------
    endfunction Get_Unit
  
  ! XLF error : "The result of an elemental function must be a nonpointer, nonallocatable scalar, and its type parameters must be constant expressions."
    function Upper_Case(string)
    !---------------------------------------------------------------------------------------------------------------------------------
    !< Function for converting lower case characters of a string to upper case ones.
    !<
  