anchor.diff:  c
   c...  open output files
   c
  -      ierr=0
  -      if(idout.gt.0) open(kw,file=ofile,status="old",access="append")
  -      if(idsk.eq.0) open(kp,file=pfile,status="old",access="append")
  -      if(idsk.eq.1) open(kp,file=pfile,status="old",access="append",
  -     & form="unformatted")
  +      ierr=izero
  +      if(idout.gt.izero) open(kw,file=ofile,err=10,status="old",
  +     & access="append")
  +      if(idsk.eq.izero) open(kp,file=pfile,err=10,status="old",
  +     & access="append")
  +      if(idsk.eq.ione) open(kp,file=pfile,err=10,status="old",
  +     & access="append",form="unformatted")
   c
   c...  output plot results
   c
  -      if(idsk.eq.0) then
  -	write(kp,"(3i7)") matnum,mattype,nprop
  -	write(kp,"(1pe15.8,20(2x,1pe15.8))") (prop(i),i=1,nprop)
  -      else if(idsk.eq.1) then
  -	write(kp) matnum,mattype,nprop
  -	write(kp) prop
  +      if(idsk.eq.izero) then
  +	write(kp,"(3i7)",err=20) matnum,mattype,nprop
  +	write(kp,"(1pe15.8,20(2x,1pe15.8))",err=20) (prop(i),i=1,nprop)
  +      else if(idsk.eq.ione) then
  +	write(kp,err=20) matnum,mattype,nprop
  +	write(kp,err=20) prop
         end if
   c
   c...  output ascii results, if desired
   c
  -      if(idout.gt.0) then
  -	write(kw,700) matnum,modelname,nprop
  +      if(idout.gt.izero) then
  +	write(kw,700,err=20) matnum,modelname,nprop
   	do i=1,nprop
  -	  write(kw,710) labelp(i),prop(i)
  +	  write(kw,710,err=20) labelp(i),prop(i)
           end do
         end if
  +c
  +      return
  +c
  +c...  error returns
  +c
  + 10   continue
  +        ierr=2
  +        errstrng="mat_prt_1"
  +        return
  + 20   continue
  +        ierr=4
  +        errstrng="mat_prt_1"
  +        return
   c
    700  format("Material number:   ",i7,/,10x,a80,/,
        &       "Number of properties:  ",i7,/)
    710  format(15x,a15,3x,1pe15.8)
   c
  -      return
         end
   c
   c
  
positive.code: c     solution.
  c     Note that only the upper triangle is used (or available), as
  c     dmat is assumed to always be symmetric.
  c     Note also that
  c
        include "implicit.inc"
  c
  
negative.code: c                                          Young's modulus
  c                                          Poisson's ratio
  c
        subroutine mat_prt_1(prop,nprop,matnum,idout,idsk,kw,kp,
       & ofile,pfile,ierr,errstrng)
  c
  c...  subroutine to output material properties for material model 1.
  c
  c     Error codes:
  c         2:  Error opening output file
  c         4:  Write error
  c
        include "implicit.inc"
  c
  c...  parameter definitions
  c
        include "nconsts.inc"
  c
  c...  subroutine arguments
  c
        integer nprop,matnum,idout,idsk,kw,kp,ierr
        double precision prop(nprop)
        character ofile*(*),pfile*(*),errstrng*(*)
  c
  c...  parameters
  c
  