Le 04/05/10 18:24, Dirk Eddelbuettel a écrit :

On 4 May 2010 at 18:02, Romain Francois wrote:
| Le 04/05/10 15:18, Douglas Bates a écrit :
|>  As I understand it, we are still at risk of code in the R API that we
|>  call in turn calling Rf_error, right?  That will have the same effect
|>  of leaving the C++ exception stack in an inconsistent state?
|
| Yes. While we do our best to isolate this problem, it is still a
| possibility.
|
| We need to track down all calls to R APIs in Rcpp and be careful about
| potential jumps. This is probably going to be difficult to track, fix or
| even test that we fixed it, because apparently the incubating period is
| unpredictable (if I understand what Simon wrote) and the symptoms could
| be quite unrelated. should be fun.
|
| One thing I am not sure at all is how the old api behaves with regards
| to exceptions and R error mechanism, and I'm not volunteering to look.

A bit of separation of church and state -- the old API was used mostly in
what I tend to call 'vertical mode': called from R in a synchronous manner,
does some work, returns.  This leaves less scope for errors as the code was
mostly in C++ outside the R API.  Also, most calls were from try / catch
blocks.

The new API is more ambitious and allows for more things in C++ and R
interchangeably (and I tend to call that 'horizontal') so there is indeed a
possibility of jumping put at the wrong time.

I'm not entirely sure how to make this water-tight.

Sure. What we need to do is check R api calls, things like STRING_ELT might call error if the object is not a STRSXP and this would invalidate C++ stack (in theory ...)

One thing the old api does not do is throw declarations and we've noticed that this sometimes makes a difference when using dynamic linking, although the old api only used standard exception classes (range_error, etc ...) and not custom classes, so maybe that makes a difference.


--
Romain Francois
Professional R Enthusiast
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
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