Re: [PATCH] Avoid non-C++-enabled babeltrace versions

[Andreas Arnez <arnez@linux.vnet.ibm.com>]

On Wed, Apr 27 2016, Pedro Alves wrote:

> On 04/27/2016 12:04 PM, Andreas Arnez wrote:
>> In some babeltrace versions before 1.2.0, the header file iterator.h is
>> not fully enabled for use from C++, since it contains an anonymous enum
>> in a struct declaration.  This is fixed in later babeltrace versions:
>> 
>>   https://lists.lttng.org/pipermail/lttng-dev/2013-September/021411.html
>> 
>
> The rationale for that commit is actually wrong.  There's nothing 
> wrong with anonymous enums in structs in C++, and being anonymous is
> actually irrelevant.   The problem is that a struct/class establishes a scope
> in C++, but not in C.  So outside the struct, to refer to the enum values,
> you'd have to write bt_iter_pos::BT_SEEK_TIME etc.

Right, the enum being anonymous does not cause a problem by itself.
Changed the commit message to avoid that impression.

>
> Anyway ...
>
>> Now that GDB is compiled with C++, the GDB build fails on a system with
>> such a babeltrace version: the compiler complains about a missing
>> declaration of BT_SEEK_BEGIN in ctf.c.
>> 
>> This patch enhances the configure check to recognize such babeltrace
>> versions as unusable for GDB.
>> 
>> gdb/ChangeLog:
>> 
>> 	* configure.ac: Enhance configure check for babeltrace to reject
>> 	non-C++-enabled versions.
>> 	* configure: Regenerate.
>
> OK.

Thanks, pushed after adjusting the commit message.

--
Andreas