From j@goreck| @end|ng |rom w|t@edu@p|  Sun Sep 15 16:36:02 2019
From: j@goreck| @end|ng |rom w|t@edu@p| (Jan Gorecki)
Date: Sun, 15 Sep 2019 16:36:02 +0200
Subject: [Rd] REprintf could be caught by tryCatch(message)
Message-ID: <CAOO9MKX_GeeVYbUCZtn688ZTq06Ue4vGeZcUTMnGxiWG+JBZhQ@mail.gmail.com>

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



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