I experimented with this earlier, but it is indeed tricky business. Last I tried my registered finalizer addressed unmapped memory, because garbage collection happened after my package (and thus the clean-up stuff) was unloaded. This happened using the R_RegisterFinalizerEx function from C++ on some dummy SEXP object.
Since cholmod_finish is an exported function from the Matrix package, it has to be called before the Matrix package is unloaded. I will try something like >> reg.finalizer(environment(Matrix), fun, onexit=TRUE) Thanks. On Mon, Mar 26, 2012 at 4:21 PM, Duncan Murdoch <murdoch.dun...@gmail.com> wrote: > On 26/03/2012 6:24 AM, Henrik Alsing Friberg wrote: >> >> Hi R-help users.. >> >> I mistakenly posted a now rejected bug report >> (https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=14855), but the >> subject still bugs me..! >> >> If I have a package called MyPackage with C code inside, then library >> or require(MyPackage) will call loadNamespace() which will look for >> and call: >> void R_init_MyPackage(DllInfo *info) >> >> At the end of the R session, the corresponding unload function is >> however *not* called. >> void R_unload_MyPackage(DllInfo *info) >> >> I use the two functions to call R_cholmod_start(CHM_CM) and >> cholmod_finish(CHM_CM) respectively, and I think this might leak >> memory if the latter is not called. Firstly, why is one called without >> the package maker having to think about it, while the other is not? >> Secondly, how do I make sure that the unload function is called -- >> using either .Last.lib or .onUnload to call unloadNamespace() seems >> like a bad idea, as unloadNamespace() is documented to call back to >> these hooks (the call cycle would have to by broken by other means)? > > > You would normally use reg.finalizer() for this, or the C level equivalents > (see the section on external pointers in Writing R Extensions). > > Duncan Murdoch ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
