anchor.diff:  c
    20   continue
           ierr=1
  +        errstrng="read_diff"
           close(kr)
           return
   c
  
positive.code:       end
  c
  c version
  c $Id: read_diff.f,v 1.1 2004/04/14 21:18:30 willic3 Exp $
  c
  c Generated automatically by Fortran77Mill on Wed May 21 14:15:03 2003
  c
  
negative.code: c
   30   continue
          ierr=3
          errstrng="read_diff"
          close(kr)
          return
  c
  c...  error opening output file
  c
   40   continue
          ierr=2
          errstrng="read_diff"
          close(kw)
          return
  c
  c...  error writing to output file
  c
   50   continue
          ierr=4
          errstrng="read_diff"
          close(kw)
          return
  c
   6000 format(//' differential forces on slippery nodes'//
  