[dpdk-dev] [RFC PATCH 1/5] graph: introduce graph subsystem

[Jerin Jacob]

On Sun, Feb 2, 2020 at 4:08 PM Stephen Hemminger
<stephen at networkplumber.org> wrote:
>
> On Fri, 31 Jan 2020 22:31:57 +0530
> <jerinj at marvell.com> wrote:
>
> > +
> > +#define set_err(err, where, fmt, ...) do {                                  \
> > +     graph_err(fmt, ##__VA_ARGS__);                                         \
> > +     rte_errno = err;                                                       \
> > +     goto where;                                                            \
> > +} while (0)
>
> I dislike this macro, it makes static analysis harder and requires
> the reader to know that the argument is a goto target. And since it is lower
> case, implies that it is a function. Usually macros are in upper case.
>
> It makes the code smaller but a cost of being different which impacts the
> readability of the code.

I don't like macro either. That's the only case where I have used
macro, Even in the fast path,
I did multiple rework to remove macro. Without that macro, that code bloats
and will have a lot repeatable code. I have a preference in using _goto_ to have
a unified exit to simply the stuff and therefor maintain the code.
You could see the amount of verification done in rte_graph_create(). So, IMO,
In this case, it is justified to use the macro.