It's not always clear when it's safe to remove the DLL. The main problem that I'm aware of is that native objects with finalizers might still exist (created by R_RegisterCFinalizer etc). Even if there are no live references to such objects (which would be hard to verify), it still wouldn't be safe to unload the DLL until a full garbage collection has been done.
If the DLL is unloaded, then the function pointer that was registered now becomes a pointer into the memory where the DLL was, leading to an almost certain crash when such objects get garbage collected. A better approach would be to just remove the limit on the number of DLLs, dynamically expanding the array if/when needed. On Tue, Dec 20, 2016 at 3:40 AM, Jeroen Ooms <jeroen.o...@stat.ucla.edu> wrote: > On Tue, Dec 20, 2016 at 7:04 AM, Henrik Bengtsson > <henrik.bengts...@gmail.com> wrote: >> On reason for hitting the MAX_NUM_DLLS (= 100) limit is because some >> packages don't unload their DLLs when they being unloaded themselves. > > I am surprised by this. Why does R not do this automatically? What is > the case for keeping the DLL loaded after the package has been > unloaded? What happens if you reload another version of the same > package from a different library after unloading? > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
