On Wed, 2013-01-16 at 12:04 -0500, Mike Frysinger wrote:
> On Wednesday 16 January 2013 10:47:12 Ben Hutchings wrote:
> > On Wed, 2013-01-16 at 23:21 +0900, YOSHIFUJI Hideaki wrote:
> > > Cong Wang wrote:
> > > > (Cc'ing some glibc developers...)
> > > >
> > > > Hello,
> > > >
> > > > In glibc source file inet/netinet/in.h and kernel source file
> > > > include/uapi/linux/in6.h, both define struct in6_addr, and both are
> > > > visible to user applications. Thomas reported a conflict below.
> > > >
> > > > So, how can we handle this? /me is wondering why we didn't see this
> > > > before.
> >
> > [...]
> >
> > > This is not a new issue. In addition to this,
> > > netinet/in.h also conflits with linux/in.h.
> > >
> > > We might have
> > >
> > > #if !defined(__GLIBC__) || !defined(_NETINET_IN_H)
> > >
> > > #endif
> > >
> > > around those conflicting definitions in uapi/linux/in{,6}.h.
> >
> > This only solves half the problem, as <netinet/in.h> might be included
> > after <linux/in.h>. Also, not all Linux userland uses glibc.
>
> certainly true, but the current expectation is that you don't mix your ABIs.
Whose expectation? Which ABIs are being mixed?
> if you're programming with the C library API, then use the C library headers.
>
> if you're banging directly on the kernel, then use the kernel headers. not
> saying it's a perfect solution, but it works for the vast majority of use
> cases.
In practice most C programs for Linux will use a mixture of thinly
wrapped system calls and higher-level APIs from the C library, and never
really call the kernel directly (as that requires inline assembler).
Userland programmers will work around this historical mess by tweaking
the #include order or splitting source files. But they shouldn't have
to.
Ben.
--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
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