Messages in this thread | | | From | Mike Frysinger <> | Subject | Re: Redefinition of struct in6_addr in <netinet/in.h> and <linux/in6.h> | Date | Wed, 16 Jan 2013 14:29:30 -0500 |
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On Wednesday 16 January 2013 13:57:44 David Miller wrote: > From: Mike Frysinger <vapier@gentoo.org> > > certainly true, but the current expectation is that you don't mix your > > ABIs. 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. > > This isn't how real life works. > > GLIBC itself brings in some of the kernel headers, as do various library > headers for libraries other than glibc. > > So you can get these conflicting headers included indirectly, and it is > of no fault of any of the various parties involved.
the headers glibc includes tend to be pretty stand alone specifically so that it doesn't matter
> We have to make them work when included at the same time somehow, and > this is totally unavoidable.
"them" is vague. saying that every kernel header has to be usable in the same compilation unit as every C library header regardless of order is unrealistic (at least it is today). there are cases where they define the same structure different because the structure as the C library expects is different from what the kernel syscall expects. you could avoid that on the kernel side by giving them all prefixes (like __kernel_), but that didn't seem entirely palpable to the kernel folks. i couldn't even get them to remove crap that breaks non- glibc C libraries (e.g. uapi/linux/stat.h -- looks like someone inadvertently fixed uapi/linux/socket.h finally).
for many networking headers, the C library will provide enums & defines while the kernel only provides enums. including the kernel after the C library one leads to parsing errors as the defines expand in the enum and kill it. like linux/in.h and netinet/in.h and IPPROTO_*. -mike [unhandled content-type:application/pgp-signature] | |