[CM] possible bug in hook invocation

[Woody Douglass]

It's a small part of a big program, so i may not be able to boil it
down to a small example but i'll try. in the meantime, i'll try your
other suggestions and report back. thanks for your help!

-Woody

On Wed, 2022-06-08 at 14:45 -0700, bil at ccrma.Stanford.EDU wrote:
> This could be a GC problem, but it's a circuitous path if so.
> Can you send me enough code to try to recreate the segfault?
> On the other question, a lambda form is only deemed safe
> if its body is safe.  If you hit the segfault in gdb,
> a stacktrace would be helpful.  To see if the GC is
> the problem, build s7 with -g3 and S7_DEBUGGING=1, then
> when you crash in safe_closure_p_a_1
> 
> p sc->code[0]
> 
> It should be a "closure" in s7 terminology (type==39 in the gdb
> output).  If it's free (type==0), go to the end of the gdb
> printout, and you'll see where the GC freed it and so on.
> (Actually S7_DEBUGGING will tell you most of this before
> falling into gdb).
>