[R] tracing the origin of warning messages

[Thomas Wutzler]

Dear R Users,

what is the best way to trace the origin of warning messages?

If an error occurs I can use traceback() to see where it comes from. I
would like to do similar investigation, where a warning message
originates from.
Is there an option to turn warnings to errors?

I tried the following
> fWarn <- function(){ warning("A") }
> options(warning.expression = stop())
> fWarn()
> traceback()
2: stop()
1: options(warning.expression = stop())

Hence, it does not give me the desired stack trace and the information
that the warning occured in function fWarn, so far.

(using Windows XP, R version 2.10.1)

Best regards
Thomas Wutzler