Flush text files (only out_unit, res_unit, lpc_unit, and parity_unit)
subroutine flush_files
implicit none
if (.not. write_ascii) return
flush (out_unit)
if (write_verr) then
flush (res_unit)
flush (lpc_unit)
end if
if (write_parity) flush (parity_unit)
end subroutine flush_files