Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> writes: > The C99 section of the CodingGuidelines is a good overview of what we > can use, but is sorely lacking in what we can't use. Something that > comes up occasionally is the portability of %z. > > Per [1] we couldn't use it for the longest time due to MSVC not > supporting it, but nowadays by requiring C99 we rely on the MSVC > version that does, but we can't use it yet because a C library that > MinGW uses doesn't support it. > > 1. https://lore.kernel.org/git/a67e0fd8-4a14-16c9-9b57-3430440ef93c@xxxxxxxxx/ > > Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> > --- > Documentation/CodingGuidelines | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines > index f9affc4050a..893f960231f 100644 > --- a/Documentation/CodingGuidelines > +++ b/Documentation/CodingGuidelines > @@ -235,6 +235,13 @@ For C programs: > . since late 2021 with 44ba10d6, we have had variables declared in > the for loop "for (int i = 0; i < 10; i++)". > > + New C99 features that we cannot use yet: > + > + . %z and %zu as a printf() argument for a size_t (the %z being for > + the POSIX-specific ssize_t). Instead you should use > + printf("%"PRIuMAX, (uintmax_t)v); These days the MSVC version we > + rely on supports %z, but the C library used by MinGW does not. > + Good. s/; These days/; these days/, though.
