Just to be 100% clear, the finalizer is called *at most* once if (as in tcltk) R_RegisterCFinalizer is called. If you want it to be called exactly once, you need to use R_RegisterCFinalizerEx.
The issue is that there may not be a final gc(). BTW, str(x) is destructive here too, so we do need to improve str(). I have code written, but access to svn.r-project.org is down (yet again). > x <- as.tclObj(pi) > str(x) Class 'tclObj' length 1 <pointer: 0x860c3f8> > str(x) length 1 <pointer: 0x860c3f8> On 31 Oct 2004, Peter Dalgaard wrote: > Simon Urbanek <[EMAIL PROTECTED]> writes: > > > Now, hold on a second - I thought the main point of EXTPTR is that the > > finalizer is called only once, that is when the last instance of the > > reference is disposed of by the gc (no matter how many copies existed > > meanwhile). Am I wrong and/or did I miss something? I did some tests > > which support my view, but one never knows ... > > How do you ensure that the finalizer is called once? By *not* copying > the reference object! You can have as many references to it as you > like (i.e. assign it to multiple variables), and the object itself is > not removed until the last reference is gone, but if you modify the > object (most likely by setting attributes, but you might also change > the C pointer payload in a C routine), all "copies" are changed: > > > x <- as.tclObj(pi) > > x > <Tcl> 3.14159265359 > > y <- x > > y > <Tcl> 3.14159265359 > > mode(x) > [1] "externalptr" > > attr(x, "Simon") <- "Urbanek" > > attributes(y) > $class > [1] "tclObj" > > $Simon > [1] "Urbanek" -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
