Re: Don't depend on obsolete Guile features. (issue 109230043 by address@hidden)

[Devon Schudy]

address@hidden wrote:
> https://codereview.appspot.com/109230043/diff/1/lily/general-scheme.cc#newcode269
> lily/general-scheme.cc:269: protects are no longer needed in Guile 2.
> What does "are no longer needed" mean?

I thought Guile 2's GC would look for pointers in the heap, so
protects wouldn't be necessary — but after checking the manual it
seems it only does that for memory allocated with scm_gc_malloc. So
they're still needed after all. (Although the stack is scanned
automatically, which may make some protects unnecessary.)

> What happens with the gc dumps in lily.scm?

AFAICT there's no way to get the set of protected objects in Guile 2,
so there's no way to make this work. Should ly:protects give a "not
supported in Guile 2" error instead of returning #f? (And maybe
dump-gc-protects should be disabled under Guile 2, since it's
useless.)