Re: [PATCH] lib: vsprintf: add printf format conversion %M for errno strings

[Joe Perches]

On Sun, 2017-06-25 at 19:12 +0200, Enrico Weigelt, metux IT consult
wrote:
> Adding a new format conversion for *printf() and friends.

Every use of %M is going to cause gcc when using __printf to emit
a warning like:

unknown conversion type character âMâ in format [-Wformat=]

Beyond that, why is this useful?
There can't possibly be any fast-path use.
Why not just create a function that does errno/string conversions?