[R] mtext unicode failure

[e-letter]

Readers,

How to solve this unicode input error please?

> postscript("~/tmp/test.eps",width=100/25.4,height=100/25.4,horizontal=FALSE,onefile=TRUE,paper="special")
> testx<-seq(1:5)
> testy<-seq(1:5)
> plot(testy~testx)
> mtext('text (O₂)\n more text',side=3,line=1)
Warning messages:
1: In mtext("text (O₂)\n more text", side = 3, line = 1) :
  conversion failure on 'text (O₂)' in 'mbcsToSbcs': dot substituted for <e2>
2: In mtext("text (O₂)\n more text", side = 3, line = 1) :
  conversion failure on 'text (O₂)' in 'mbcsToSbcs': dot substituted for <82>
3: In mtext("text (O₂)\n more text", side = 3, line = 1) :
  conversion failure on 'text (O₂)' in 'mbcsToSbcs': dot substituted for <82>
4: In mtext("text (O₂)\n more text", side = 3, line = 1) :
  conversion failure on 'text (O₂)' in 'mbcsToSbcs': dot substituted for <e2>
5: In mtext("text (O₂)\n more text", side = 3, line = 1) :
  conversion failure on 'text (O₂)' in 'mbcsToSbcs': dot substituted for <82>
6: In mtext("text (O₂)\n more text", side = 3, line = 1) :
  conversion failure on 'text (O₂)' in 'mbcsToSbcs': dot substituted for <82>

If the command to print to postscript is omitted, a graph is viewed
successfully, with the title text:

text(O₂)
more text

Thanks.

--
r2151