Messages in this thread | | | Subject | Re: [PATCH] lib: vsprintf: add printf format conversion %M for errno strings | From | "Enrico Weigelt, metux IT consult" <> | Date | Sun, 25 Jun 2017 21:53:02 +0200 |
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On 25.06.2017 19:27, Joe Perches wrote:
> Every use of %M is going to cause gcc when using __printf to emit > a warning like: > > unknown conversion type character ‘M’ in format [-Wformat=]
Yeah, that's still an open problem. Actually, I still haven't found out, how it's done w/ all the other kernel-internal conversions. I was under the impression, there was some magic to tell the compiler which letters correspond to which types - unfortunately, didn't find anything like that. Is that really hardcoded in gcc ?
> Beyond that, why is this useful?
Use that instead of %d where errno values are printed/logged.
> There can't possibly be any fast-path use.
I'm using it eg. for driver development - always having to look up the numbers is quite ugly and time consuming.
> Why not just create a function that does errno/string conversions?
Already was about to do so. Shall I call it strerror() ?
--mtx
-- Enrico, Sohn von Wilfried, a.d.F. Weigelt, metux IT consulting +49-151-27565287
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