Re: trouble with scm_display_backtrace in guile 1.8.3

[Ludovic Courtès]

Hi,

(I must confess I'd be more comfortable with the same piece of code in
Scheme...  Generally, I find it more convenient to have the boot code as
a Guile script which then loads all the relevant pieces of C code.
Scheme code is also less likely to break with future Guile versions.)

"René Köcher" <address@hidden> writes:

>                 SCM stack = scm_fluid_ref(
>                             SCM_VARIABLE_REF(scm_the_last_stack_fluid_var));
>                 SCM subr  = SCM_CAR(args);
>                 SCM mesg  = SCM_CADR(args);
>                 SCM cargs = SCM_CADDR(args);
> #if 1
>                 /* FIXME: still wrong-type-arg error.. */
>                 scm_display_backtrace(stack, scm_current_error_port(),
>                                       SCM_UNDEFINED, SCM_UNDEFINED);

Presumably STACK is `#f' here, can you confirm it (e.g., by
`scm_write'ing it)?  If so, then this means that `SCM_DEBUG_P' is
somehow not taken into account.

In theory, what you propose should work:

  guile> (define (foo x)
           (catch #t
             (lambda () (error "sdf"))
             (lambda args (fluid-ref the-last-stack))))
  guile> (foo 2)
  #<stack 8050fc0:b7a8dbf0>

As you can see, the error handler gets to see a valid stack when looking
at THE-LAST-STACK.

Thanks,
Ludovic.