anchor.diff:    if (urst > 0) then
        call read_rst(urst,data_format,nvars,nclasses,iproc,nproc,seq,prm,err)
        if (err /= 0) then
  +        if(iproc == 0) write(0,*) 'ERROR ! cannot read from rst'
           call mpi_wrapper_finalize(err)
           stop
        end if
  
positive.code:        nvars,nclasses,nseqs,neff,seqs,err,err_string)
  
    if (err /= 0) then
       call mpi_wrapper_finalize(err)
       stop
    end if
  
negative.code:   close(udata)
  
    ! open output
    call units_open(trim(mode)//'.log','unknown',ulog,err)
    if(err /= 0) then
       if (iproc == 0) write(0,*) "error opening file ", trim(mode)//'.log'
  