Messages in this thread | | | From | Rob Landley <> | Subject | git 9c501935a3cd broke the strace build. | Date | Thu, 14 Jan 2010 04:57:00 -0600 |
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> net: Support inclusion of <linux/socket.h> before <sys/socket.h> > > The following user-space program fails to compile: > > #include <linux/socket.h> > #include <sys/socket.h>
Did it ever? Isn't #including both sys/thingy and a linux/thingy in the same program considered bad form?
> int main() { return 0; } > > The reason is that <linux/socket.h> tests __GLIBC__ to decide whether it > should define various structures and macros that are now defined for > user-space by <sys/socket.h>, but __GLIBC__ is not defined if no libc > headers have yet been included.
Specifically, one of the tests was !__GLIBC__, I.E. checking that we _haven't_ included any of glibc's headers yet, which is presumably how you broke the strace 4.5.18 ./configure test checking for the existence of the linux/netlink.h file. (That test #includes stddef.h, linux/socket.h, and linux/netlink.h and nothing else. Since stddef.h is a gcc header and not a glibc header, __GLIBC__ isn't defined for the test code and thus that used to work under 2.5.31. Now under 2.6.32 it dies with:
linux/netlink.h:35: error: expected specifier-qualifier-list before 'sa_family_t'
And later on the strace build breaks because it doesn't #include linux/netlink.h when it needs to. (Why yes, autoconf _is_ brittle and near- useless, thanks for noticing.)
*shrug* I can patch the strace ./configure to include bits/socket.h instead of linux/socket.h, but what I can't understand is why _you_ couldn't. (What use case did this patch actually fix? Would reversing the order of those two headers have helped?)
Rob -- Latency is more important than throughput. It's that simple. - Linus Torvalds
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