[Rcpp-devel] experimental c++ stack trace

[Romain Francois]

Hello,

I've commited some experimental mechanism based on this blog post 
:http://tombarta.wordpress.com/2008/08/01/c-stack-traces-with-gcc/

This uses the backtrace_symbols function (see 
http://www.gnu.org/s/libc/manual/html_node/Backtraces.html) to grab a 
stack trace.

The main entry point is the Rcpp_error macro that is used similarly to 
Rf_error, but it gathers more information. For example :

require( inline )
require( Rcpp)

inspect <- function(...) .Internal(inspect(...))
fx <- cfunction( signature( l = "list" ), '
	Rcpp_error( "boom" ) ;
', Rcpp = TRUE, includes = "using namespace Rcpp;" )

tryCatch( fx( poisson() ), "error" = function(e) print(str(e)) )

prints out this :

List of 3
  $ message : chr "unrecognized exception"
  $ call    : language fx(poisson())
  $ cppstack:List of 3
   ..$ file : chr "file10d63af1.cpp"
   ..$ line : int 11
   ..$ stack: chr [1:47] "Rcpp::exception::exception(char const*, char 
const*, int)" "file10d63af1" "do_dotcall" "Rf_eval" ...
   ..- attr(*, "class")= chr "Rcpp_stack_trace"
  - attr(*, "class")= chr [1:4] "Rcpp::exception*" "C++Error" "error" 
"condition"

The interesting bit is the cppstack which indicates :
- the file from which Rcpp_error was called
- the line of
- the stack of calls, demangled

I'd appreciate suggestions on the interface, should we have a nice print 
function at the R level, etc ...


Romain


-- 
Romain Francois
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http://romainfrancois.blog.free.fr
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