[R-SIG-Mac] Help with locale on OS X

[Don MacQueen]

For several years I've been running scripts with this expression

   substr(tmp.un[substr(tmp.un,1,1)=='u'],1,1) <- '\265'

whose purpose is to replace the letter 'u' with a 
Greek mu, to change, for example,  'ug/L' to 
'µg/L'. It has been working over several versions 
of R.

Recently, I started (sometimes?) getting error messages from the expression:

>  substr(tmp.un[substr(tmp.un,1,1)=='u'],1,1) <- '\265'
Error in "substr<-"(`*tmp*`, 1, 1, value = "<b5>") :
         invalid multibyte string

In the same R session:

>  Sys.getlocale()
[1] "C/en_US.UTF-8/C/C/C/C"

Yet, in another R session on the same machine (in a different directory)

>  Sys.getlocale()
[1] "C"

If I go back to the first session, that had the problem, and do
    > Sys.setlocale('LC_ALL','C')
then the error goes away. This is good.

But I have no idea why the locale is apparently 
getting set wrong; I don't believe I ever 
explicitly wrote a "set locale" expression of any 
sort anywhere in the scripts for this project. 
Maybe it's a side effect of something, but I 
don't know what.

Any suggestions would be most appreciated.

Thanks
-Don

>  sessionInfo()
R version 2.2.1, 2005-12-26, powerpc-apple-darwin7.9.0

attached base packages:
[1] "stats"   "utils"   "methods" "base"

other attached packages:
  xtable   rmacq ROracle     DBI
"1.3-0"   "1.0" "0.5-5" "0.1-9"

(and I will move to 2.3.0 soon)
-- 
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA