Compilation issues using netlink.h

Hi,

The test case below simplifies a failure I see when trying to compile strace using kernel headers from Linux-2.6.32.2:

#include <linux/netlink.h>
struct sockaddr_nl nl;
int main() {
return 0;
}

$ gcc -o test test.c
In file included from test.c:1:
/usr/include/linux/netlink.h:34: error: expected specifier-qualifier-list before 'sa_family_t'

The comment in netlink.h suggests that 'sa_family_t' is expected to be found in linux/socket.h, but since commit 9c501935a3 ("net: Support inclusion of <linux/socket.h> before <sys/socket.h>") that appears to not be true anymore, it's now in sys/socket.h. Sure enough, if I change the include in netlink.h to pull in sys/socket.h instead of linux/socket.h, that enables the test case (and strace) to compile again, but I wasn't sure if it was really the right thing to do.

Thanks,

Matt.

Right. I'm aware of this and suggested that it should be reverted, but David Miller reckons I was right in the first place.

I don't think it is - that will bring in many more definitions.

There are actually a whole lot of kernel networking headers which require sa_family_t when included by user-space code. Until <linux/socket.h> and <sys/socket.h> cooperate to define sa_family_t once, you will just have to include <sys/socket.h> before kernel networking headers.

Ben.

Ben Hutchings
The obvious mathematical breakthrough [to break modern encryption] would be
development of an easy way to factor large prime numbers. - Bill Gates