[lttng-dev] [RFC PATCH CTF 1/3] Clarify that unlisted enum values are implementation-defined

[Jérémie Galarneau]

On Thu, 23 Apr 2020 at 16:52, Mathieu Desnoyers
<mathieu.desnoyers at efficios.com> wrote:
>
> From: Geneviève Bastien <gbastien+lttng at versatic.net>
>
> Signed-off-by: Geneviève Bastien <gbastien+lttng at versatic.net>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> ---
>  common-trace-format-specification.md | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/common-trace-format-specification.md b/common-trace-format-specification.md
> index fd49e59..f5fea51 100644
> --- a/common-trace-format-specification.md
> +++ b/common-trace-format-specification.md
> @@ -464,6 +464,9 @@ enum {
>  }
>  ~~~
>
> +The mappings in the enumeration type do not have to be exhaustive.
> +Unlisted values are implementation defined.
> +

This is too vague to be useful knowing that the main rationale for this
change is to allow enums to express some type of bitfield of flags
in the tracer and readers [1].

What is the meaning of an unmapped value? This section should at
least describe the correct interpretation of unmapped values as flags
and when it is appropriate to do so.

Thanks,
Jérémie

[1] https://review.lttng.org/c/babeltrace/+/3045

>  ### 4.2 Compound types
>
>  Compound are aggregation of type declarations. Compound types include
> --
> 2.11.0
>


-- 
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com