On Wed, Aug 10, 2016 at 9:11 AM Yichao Yu <yyc1...@gmail.com> wrote: > On Wed, Aug 10, 2016 at 2:17 PM, Kit Adams <kit.ad...@gmail.com> wrote: > >> I am investigating the feasibility of embedding Julia in a C++ real-time >> signal processing framework, using Julia-0.4.6 (BTW, the performance is >> looking amazing). >> >> However, for this usage I need to retain Julia state variables across c++ >> function calls, so the stack based JL_GC_PUSH() and JL_GC_POP() are not >> sufficient. >> When I injected some jl_gc_collect() calls for testing purposes, to >> simulate having multiple Julia scripts running (from the same thread), I >> got crashes, which I was able to fix using e.g. jl_gc_preserve(mMyState); >> and appropriate matching jl_gc_unpreserve() calls. >> >> I see these functions have been removed from the latest Julia version. >> >> Is there an alternative that allows Julia values to be retained in a C++ >> app across gc calls? >> > > Copy from my reply on github > > > This never works in the way you think it did. For keeping a value live, > put it in a rooted global array. > > > I'm not saying this is the best way to implement Yichao's suggestion, but here is how it's done in CxxWrap.jl: https://github.com/barche/CxxWrap.jl/blob/master/deps/src/cxx_wrap/type_conversion.hpp#L27-L38
The array is allocated and rooted using jl_set_const here: https://github.com/barche/CxxWrap.jl/blob/master/deps/src/cxx_wrap/cxx_wrap.cpp#L14-L28 Cheers, Bart
