Re: [patch+7.8?] Fix --with-babeltrace with gcc-4.9.1

[Doug Evans <dje@google.com>]

On Tue, Aug 12, 2014 at 1:38 PM, Jan Kratochvil
<jan.kratochvil@redhat.com> wrote:
> On Tue, 12 Aug 2014 22:32:55 +0200, Doug Evans wrote:
>> E.g., can we just delete "pos" and the function call that initializes it?
>>
>> struct bt_iter_pos *pos = bt_iter_get_pos (bt_ctf_get_iter (NULL));
>
> I think we cannot and the reason is given in the comment there:
>   # Append -Werror to CFLAGS so that configure can catch the warning
>   # "assignment from incompatible pointer type", which is related to
>   # the babeltrace change from 1.0.3 to 1.1.0.  Babeltrace 1.1.0 works
>   # in GDB, while babeltrace 1.0.3 is broken.
>
>
>> Or, if for some reason we need to test whether bf_ctf_get_iter exists,
>> can we just
>> call it and discard the result?
>
> Also not due to the reason above.

Alas the comment doesn't specify which assignment.
I think it's for scope.

I did some grepping:

@ruffy:babeltrace$ find babeltrace-1.0.3 -name '*.h' | xargs grep
bt_iter_get_pos
babeltrace-1.0.3/include/babeltrace/iterator.h: * - restore is a
position saved with bt_iter_get_pos, it is used with
babeltrace-1.0.3/include/babeltrace/iterator.h: * bt_iter_get_pos -
Get the current iterator position.
babeltrace-1.0.3/include/babeltrace/iterator.h:struct bt_iter_pos
*bt_iter_get_pos(struct bt_iter *iter);
@ruffy:babeltrace$ find babeltrace-1.1.0 -name '*.h' | xargs grep
bt_iter_get_pos
babeltrace-1.1.0/include/babeltrace/iterator.h: * - restore is a
position saved with bt_iter_get_pos, it is used with
babeltrace-1.1.0/include/babeltrace/iterator.h: * bt_iter_get_pos -
Get the current iterator position.
babeltrace-1.1.0/include/babeltrace/iterator.h:struct bt_iter_pos
*bt_iter_get_pos(struct bt_iter *iter);
@ruffy:babeltrace$ find babeltrace-1.0.3 -name '*.h' | xargs grep
bt_ctf_get_top_level_scope
babeltrace-1.0.3/include/babeltrace/ctf/events.h: *
bt_ctf_get_top_level_scope: return a definition of the top-level scope
babeltrace-1.0.3/include/babeltrace/ctf/events.h:const struct
definition *bt_ctf_get_top_level_scope(const struct bt_ctf_event
*event,
@ruffy:babeltrace$ find babeltrace-1.1.0 -name '*.h' | xargs grep
bt_ctf_get_top_level_scope
babeltrace-1.1.0/include/babeltrace/ctf/events.h: *
bt_ctf_get_top_level_scope: return a definition of the top-level scope
babeltrace-1.1.0/include/babeltrace/ctf/events.h:const struct
bt_definition *bt_ctf_get_top_level_scope(const struct bt_ctf_event
*event,

Note that there's no change in the result of bt_iter_get_pos, but
there is in bt_ctf_get_top_level_scope.

Plus some digging found this:
https://sourceware.org/ml/gdb-patches/2013-03/msg00955.html