Oh, and the same will happen with GC_get_suspend_signal, which we define at scmsigs.c:155.
Other than that, though, the new gc resolves the problem I had. I am willing to chalk this up to a GC bug and not worry about it more. Noah On Tue, Feb 7, 2012 at 9:07 AM, Noah Lavine <noah.b.lav...@gmail.com> wrote: > Hello, > > I inserted a GC_is_visible check in my code and learned that 'symbols' > is visible, but the things it points to were getting garbage collected > anyway. It seemed like a GC bug, so I'm trying to build Guile with the > latest version of GC and hoping that fixes it. > > I just wanted to warn everyone that the GC_get_free_space_divisor > function will break with libgc 7.2alpha6, because libgc includes the > same function with the same name. I'm not sure what to do about that - > probably try to automatically discover it in configure and put more > #ifdefs around our definition (gc.c:212). > > Noah > > On Thu, Feb 2, 2012 at 9:59 PM, Noah Lavine <noah.b.lav...@gmail.com> wrote: >> Got it! And unfortunately, it's a GC error. Here's what happens: >> >> symbols is an SCM object defined in symbols.c. It points to an >> scm_cell_t which has two elements: a type tag, and a pointer to an >> scm_weak_set_t. That scm_cell_t is at 0x10101cff0. >> >> However, that scm_cell_t is garbage collected in the scm_cons at >> symbols.c:250. The reason it gets filled with SCM_EOL is that the cons >> is scm_cons (SCM_BOOL_F, SCM_EOL). So I expect that the scm_cell_t is >> garbage collected and then immediately reclaimed to be the pair, which >> would result in its second cell being filled with SCM_EOL, which would >> explain why we later extract SCM_EOL from it. >> >> As a test, I changed the variable 'symbols' in symbols.c to be >> non-static. That didn't fix it, but then again, I don't really know >> how GC works yet. >> >> I can read the libgc documentation and try to figure this out, but can >> anyone point me to what I should be looking for? >> >> Thanks, >> Noah >> >> On Wed, Feb 1, 2012 at 4:01 AM, Andy Wingo <wi...@pobox.com> wrote: >>> On Wed 01 Feb 2012 03:12, Noah Lavine <noah.b.lav...@gmail.com> writes: >>> >>>> In the failing call, >>>> the SCM 'symbols' is 0x10101cff0, but the failing set is at 0x304, >>>> which has not been allocated. >>> >>> 0x304 is one of the iflags, SCM_EOL I think. >>> >>> So, I know it might not have anything to do with it, but can you verify >>> that your guile includes patch 0aed71aa51e89e714de2392c2a5f44694dca77ea >>> ? I just committed that last night, and although it does not seem to be >>> related, who knows. >>> >>> Andy >>> -- >>> http://wingolog.org/