On Tue, Jun 4, 2019 at 9:48 PM Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote: > > On Tue, Jun 4, 2019 at 8:55 PM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > > On Tue, Jun 4, 2019 at 1:23 PM Joe Perches <joe@xxxxxxxxxxx> wrote: > > > > > > On Tue, 2019-06-04 at 20:13 +0900, Masahiro Yamada wrote: > > > > On the other hand, uapi headers are written in more strict C, where > > > > the C++ comment style is forbidden. > > > > > > Is this a real problem for any toolchain? > > > > There is likely some code that is built with -Wpedandic -Werror --std=c89 > > or similar. Since glibc allows this combination for its own headers, it seems > > best to also allow it in kernel headers that may be included by libc headers > > or by applications, at least where it does not hurt. > > > > Realistically though, we probably assume c99 or gnu89 in user space > > headers anyway, since there is no 'long long' in earlier standards. > > > > Arnd > > In fact, I detected this issue by the following patch: > https://patchwork.kernel.org/patch/10974669/ > > When I worked on it, I wondered which > c-dialect flags should be used. > > This code: > > > # Unlike the kernel space, uapi headers are written in more strict C. > > # - Forbid C++ style comments > > # - Use '__inline', '__asm__' instead of 'inline', 'asm' > > # > > # -std=c90 (equivalent to -ansi) catches the violation of those. > > # We cannot go as far as adding -Wpedantic since it emits too many warnings. > > # > > # REVISIT: re-consider the proper set of compiler flags for uapi compile-test. > > > > UAPI_CFLAGS := -std=c90 -Wpedantic -Wall -Werror=implicit-function-declaration I got rid of -Wpedantic in the submitted patch. Sorry if I confused you. -- Best Regards Masahiro Yamada
