On Fri, 12 Oct 2018 14:43:57 +0200
Adrien Mazarguil <adrien.mazarg...@6wind.com> wrote:
> On Fri, Oct 12, 2018 at 11:45:01AM +0100, Ferruh Yigit wrote:
> > On 10/12/2018 11:42 AM, Ferruh Yigit wrote:
> > > On 10/11/2018 6:59 PM, Stephen Hemminger wrote:
> > >> @@ -161,8 +161,9 @@ extern "C" {
> > >>
> > >> extern int rte_eth_dev_logtype;
> > >>
> > >> -#define RTE_ETHDEV_LOG(level, ...) \
> > >> - rte_log(RTE_LOG_ ## level, rte_eth_dev_logtype, "" __VA_ARGS__)
> > >> +#define RTE_ETHDEV_LOG(level, fmt, ...) \
> > >> + rte_log(RTE_LOG_ ## level, rte_eth_dev_logtype, \
> > >> + "%s():" fmt, __func__, ## __VA_ARGS__)
> > >
> > > +1 to adding function name, but
> > >
> > > failsafe is giving build error [1] with clang because of ## usage [2],
> > > that is
> > > why I add this as ` "" __VA_ARGS__` at first place but you can't do this
> > > trick
> > > if __VA_ARGS__ used after fmt.
> > >
> > > I am not aware of a solution for this, __VA_OPT__(,) also didn't worked
> > > with clang.
> >
> > +cc Adrien & Gaetan,
> >
> > I saw Adrien put some "workaround" to this for mlx5
>
> Yes, through RTE_FMT() (rte_common.h). Something like this:
>
> #define RTE_ETHDEV_LOG(level, fmt, ...) \
> rte_log(RTE_LOG_ ## level, \
> rte_eth_dev_logtype, \
> "%s():" fmt, \
> __func__, \
> ## __VA_ARGS__)
>
> Can be rewritten like that:
>
> #define RTE_ETHDEV_LOG(level, ...) \
> rte_log(RTE_LOG_ ## level, \
> rte_eth_dev_logtype, \
> RTE_FMT("%s():" RTE_FMT_HEAD(__VA_ARGS__,), \
> __func__, \
> RTE_FMT_TAIL(__VA_ARGS__,)))
>
> Although not too pretty and convenient, it does the job. In short:
>
> - Remove "fmt" argument from prototype.
> - Enclose format string and its arguments in RTE_FMT().
> - Replace "fmt" with RTE_FMT_HEAD(__VA_ARGS__,).
> - Replace "## __VA_ARGS__" with RTE_FMT_TAIL(__VA_ARGS__,).
> - Yes, trailing commas are mandatory in RTE_FMT_(HEAD|TAIL)().
> - Note it quietly appends a dummy "%.0s" argument to the format string.
>
> > > [1]
> > > .../build/include/rte_ethdev.h:166:26: error: token pasting of ',' and
> > > __VA_ARGS__ is a GNU extension
> > > [-Werror,-Wgnu-zero-variadic-macro-arguments]
> > > "%s():" fmt, __func__, ## __VA_ARGS__)
> > > ^
> > >
> > > [2]
> > > This seems because of "-pedantic" argument driver uses, and other PMDs
> > > using
> > > "-pedantic", like mlx, will have same error although they are disable by
> > > default and error not observed in default build.
> > >
> >
>
Since zero varadic macros is a GNU extension, maybe just adding GNU source?
