On Tue, Jul 16, 2019 at 10:21 AM Junio C Hamano <gitster@xxxxxxxxx> wrote: > > Even though we have been sticking to C89, there are a few handy > features we borrow from more recent C language in our codebase after > trying them in weather balloons and saw that nobody screamed. > > Spell them out. > > While at it, extend the existing variable declaration rule a bit to > read better with the newly spelled out rule for the for loop. > > Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx> > --- > Documentation/CodingGuidelines | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines > index 1169ff6c8e..53903b14c8 100644 > --- a/Documentation/CodingGuidelines > +++ b/Documentation/CodingGuidelines > @@ -195,10 +195,24 @@ For C programs: > by e.g. "echo DEVELOPER=1 >>config.mak". > > - We try to support a wide range of C compilers to compile Git with, > - including old ones. That means that you should not use C99 > - initializers, even if a lot of compilers grok it. > + including old ones. That means that you should not use certain C99 > + features, even if your compiler groks it. There are a few > + exceptions: > > - - Variables have to be declared at the beginning of the block. > + . since early 2012 with e1327023ea, we have been using an enum > + definition whose last element is followed by a comma. Is there a significance to the leading . here versus a leading - below? > + > + . since mid 2017 with cbc0f81d and 512f41cf, we have been using > + designated initializers for struct and array. > + > + These used to be forbidden, but we have not heard breakage report, > + so they are assumed to be safe. With the placement here, is it possible that someone might read the “These used to be forbidden” as applying to the items that follow after it, rather than the items that preceded it? Put a different way, could there be some value in having some additional verbiage here that indicates something along the lines of “Aside from those exceptions, other C99 features are not allowed. Some common examples are:” Just a thought. (Pardon the suggestion from the peanut gallery!) > + > + - Variables have to be declared at the beginning of the block, before > + the first statement (i.e. -Wdeclaration-after-statement). > + > + - Declaring a variable in the for loop "for (int i = 0; i < 10; i++)" > + is still not allowed in this codebase. > > - NULL pointers shall be written as NULL, not as 0. > >
