Re: [PATCH resend] uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name

Andrew Morton
2018-08-29T22:56:52Z

On Tue, 28 Aug 2018 19:42:24 -0700 Greg KH <gregkh@linuxfoundation.org> wrote:

> > --- lnx-416.orig/include/uapi/linux/keyctl.h
> > +++ lnx-416/include/uapi/linux/keyctl.h
> > @@ -65,7 +65,7 @@
> >
> > /* keyctl structures */
> > struct keyctl_dh_params {
> > - __s32 private;
> > + __s32 dh_private;
>
> Ick ick ick, why not just put the C "namespace" on all uapi files if you
> are including them from c++ code? I'm sure this isn't the only problem
> that has this problem, right?
>
> This is valid C, no need to start worrying about C++ reserved names.

We've done this before and it's a simple enough change in order to be
friendly toward others.

That being said, it's been like this for two years so presumably anyone
who is using this header from C++ is already `extern "C" { ...}' around
their #include.

I'm OK with the patch as-is, but if we run into this issue more often,
we might want to look at doing something kernel-wide.

I'm not sure what though. Adding

#ifdef __cplusplus
extern "C" {
#endif

...

#ifdef __cplusplus
}
#endif

into every uapi file might work. Unpleasing.