[Rd] REprintf could be caught by tryCatch(message)

[Jan Gorecki]

Dear R-devel community,

There appears to be an inconsistency in R C API about the exceptions
that can be raised from C code.
Mapping of R C funs to corresponding R functions is as follows.

error    -> stop
warning  -> warning
REprintf -> message
Rprintf  -> cat

Rprint/cat is of course not an exception, I listed it just for completeness.
The inconsistency I would like to report is about REprintf. It cannot
be caught by tryCatch(message). Warnings are errors are being caught
as expected.

Is there any chance to "fix"/"improve" REprintf so tryCatch(message)
can catch it?
So in the example below catch(Cmessage()) would behave consistently to
R's catch(message("a"))?

Regards,
Jan Gorecki

catch = function(expr) {
  tryCatch(expr,
    message=function(m) cat("caught message\n"),
    warning=function(w) cat("caught warning\n"),
    error=function(e) cat("caught error\n")
  )
}
library(inline)
Cstop = cfunction(c(), 'error("%s\\n","a"); return R_NilValue;')
Cwarning = cfunction(c(), 'warning("%s\\n","a"); return R_NilValue;')
Cmessage = cfunction(c(), 'REprintf("%s\\n","a"); return R_NilValue;')

catch(stop("a"))
#caught error
catch(warning("a"))
#caught warning
catch(message("a"))
#caught message

catch(Cstop())
#caught error
catch(Cwarning())
#caught warning
catch(Cmessage())
#a
#NULL