Hi, On Wed, Mar 30, 2011 at 8:00 AM, John Baldwin <[email protected]> wrote: > On Tuesday, March 29, 2011 5:20:30 pm [email protected] wrote: >> I thought I knew something about how the compiler looks for include >> files, but now I think maybe I don't know much. :-) >> >> So here's what I'm pondering. When I build a library, like e.g. libc, >> where do the include files get pulled from? They can't (shouldn't) be >> the ones in /usr/include, but I don't see a -nostdinc like for the >> kernel. There are -I directives in the Makefile for >> -I${.CURDIR}/include -I${.CURDIR}/../../include, etc., but that won't >> remove /usr/include from the search path. >> >> I see in the gcc documentation that -I paths are searched before the >> standards paths. But isn't the lack of -nostdinc a bug (not just for >> libc, but for any library in /usr/src/lib)? It somewhat feels to me >> that all of the libraries and binaries in the source distribution >> should use -nostdinc and include only from the source distribution >> itself. This isn't always an issue, but for source upgrades it seems >> crucial, and for a hacker it saves difficulties with having to install >> headers before re-building. >> >> Is that the intent, and it's not fully implemented? How badly would >> things break if -nostdinc was included in e.g. bsd.lib.mk? (This would >> break non-base libraries, yes? But as a thought experiment for the >> base, how far off are we?) > > If you are building a library by hand you do want to use the includes from > /usr/include. I am not sure how we accomplish during buildworld (but we do). > I think we actually build the compiler in the cross-tools stage such that > it uses the /usr/include directory under {WORLDTMP} in place of /usr/include > in the default search path. > > Some other folks might be able to verify that (perhaps ru@?). > FWIW (I've been hacking around `buildworld' lately), yes, and the `_includes' stage is responsible to populate ${WORLDTMP}/usr/include. The same goes for ${WORLDTMP}/usr/lib and `_libraries'. That was with a 7-stable tree, I'm not sure how clang integrates in all this. The same way I suppose.
- Arnaud > -- > John Baldwin > _______________________________________________ > [email protected] mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "[email protected]" > _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[email protected]"
