f_esmf_regrid Subroutine

  subroutine f_esmf_regrid(srcField, dstField, routehandle, zeroregion, zrpresent, rc)

    use ESMF_UtilTypesMod
    use ESMF_BaseMod
    use ESMF_LogErrMod
    use ESMF_RHandleMod
    use ESMF_FieldRegridMod
    use ESMF_FieldMod

    implicit none

    type(ESMF_Field)        :: srcField
    type(ESMF_Field)        :: dstField
    type(ESMF_RouteHandle)  :: routehandle
    type(ESMF_Region_Flag)  :: zeroregion
    integer, intent(in)     :: zrpresent
    integer                 :: rc 

    integer :: localrc
    type(ESMF_RouteHandle)  :: l_routehandle
  
    ! initialize return code; assume routine not implemented
    rc = ESMF_RC_NOT_IMPL
    localrc = ESMF_RC_NOT_IMPL

    ! Must first create a proper ESMF_RouteHandle that contains the 
    ! required "isInit" class member.
    ! Copy the this pointer a new ESMF_RouteHandle object
    call ESMF_RouteHandleCopyThis(routehandle, l_routehandle, localrc)
    if (ESMF_LogFoundError(localrc, ESMF_ERR_PASSTHRU, &
      ESMF_CONTEXT, rcToReturn=rc)) return
    ! set the valid init code of the new object
    call ESMF_RouteHandleSetInitCreated(l_routehandle, localrc)
    if (ESMF_LogFoundError(localrc, ESMF_ERR_PASSTHRU, &
      ESMF_CONTEXT, rcToReturn=rc)) return

    ! handle the zeroregion flag
    if (zrpresent == 0) then
      call ESMF_FieldRegrid(srcField, dstField, routehandle=l_routehandle, &
        rc=localrc)
    elseif (zrpresent == 1) then
      call ESMF_FieldRegrid(srcField, dstField, routehandle=l_routehandle, &
        zeroregion=zeroregion, rc=localrc)
    endif
    if (ESMF_LogFoundError(localrc, ESMF_ERR_PASSTHRU, &
      ESMF_CONTEXT, rcToReturn=rc)) return
  
    rc = ESMF_SUCCESS
  
  end subroutine f_esmf_regrid