anchor.diff:         select case(trim(arg))
          case('-h','--help')
             ! print help and exit
  -          write(0,*) trim(syntax)
  +          write(0,100)
             error_code = 1
             return
          case('-p','--prm')
  
positive.code: 
      if (nargs == 0) then
         ! no args: print syntax and stop
         write(0,*) trim(syntax)
         error_code = 1
         return
      end if
  
negative.code:   implicit none
    private
    public :: command_line_read
  
  contains
  
    subroutine command_line_read(uprm,uchk,useq,rseed,beta,mc_nsweeps,nupdate,&
  