[R] tracing the origin of warning messages

[Thomas Wutzler]

Thanks Mr. Ripley, Mr. Liggers, and Mr. Burns,

"I can not see the forest, because trees block my sight"
options(warn=2)

Thanks also for the hint to the very useful R Inferno. I guess, reading
it earlier, would have saved days of debugging and frustration.
I also did not now about the useful browser, recover, and trace
functions yet.

Just of interest: Is there a way to trace the nth warning, i.e. continue
on the first n-1 warnings and stop only afterwards?

Best regards
Thomas Wutzler

Thomas Wutzler wrote:
> 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