On Tue, 4 Mar 2008, M. Warner Losh wrote: MWL>In message: <[EMAIL PROTECTED]> MWL> Giorgos Keramidas <[EMAIL PROTECTED]> writes: MWL>: On 2008-03-04 15:38, Robert Watson <[EMAIL PROTECTED]> wrote: MWL>: > On Tue, 4 Mar 2008, M. Warner Losh wrote: MWL>: > MWL>: >> : In most ports of FreeBSD parts to Linux that I've seen, the preferred solution MWL>: >> : has to been to bring the entire FreeBSD queue.h with you rather than relying MWL>: >> : on the native Linux queue.h. This is what we do for OpenBSM, for example; MWL>: >> : this also helps out when you get to Mac OS X, Solaris, etc, where all the MWL>: >> : queue.h's continue to vary in subtle ways. This depends a fair amount on a MWL>: >> : lack of header pollution in the OS's own include files, of course... MWL>: >> MWL>: >> I was rather hoping for something that could be used without any of that MWL>: >> nonsense... MWL>: > MWL>: > Sadly, nonsense seems to be the name of the game in software portability. MWL>: > Here's the broken autoconf garbage I use to pick out adequate queue.h's MWL>: > from inadequate ones: MWL>: > MWL>: > # sys/queue.h exists on most systems, but its capabilities vary a great deal. MWL>: > # test for LIST_FIRST and TAILQ_FOREACH_SAFE, which appears to not exist in MWL>: > # all of them, and are necessary for OpenBSM. MWL>: > AC_TRY_LINK([ MWL>: > #include <sys/queue.h> MWL>: > ], [ MWL>: > MWL>: > #ifndef LIST_FIRST MWL>: > #error LIST_FIRST missing MWL>: > #endif MWL>: > #ifndef TAILQ_FOREACH_SAFE MWL>: > #error TAILQ_FOREACH_SAFE MWL>: > #endif MWL>: > ], [ MWL>: > AC_DEFINE(HAVE_FULL_QUEUE_H,, Define if queue.h includes LIST_FIRST) MWL>: > ]) MWL>: > MWL>: > Note that there are at least a couple of mostly stylistic bugs there (could MWL>: > use compile rather than link, definition description is poor, errors are MWL>: > inconsistent). :-) I found that on both Linux and Mac OS X, the queue.h's MWL>: > didn't have everything I wanted. MWL>: MWL>: Nice! Thank you Robert. Can I copy parts of this and add them to the MWL>: autoconf glue I'm adding now? MWL>: MWL>: To test just cpp(1) stuff, autoconf supports AC_PREPROC_IFELSE() too, MWL>: which I used when I tried writing a check for __FBSDID(): MWL>: MWL>: AC_PREPROC_IFELSE( MWL>: [AC_LANG_PROGRAM([[#include <sys/cdefs.h> MWL>: #ifndef __FBSDID MWL>: #error No __FBSDID definition. MWL>: #endif]])], MWL>: [AC_DEFINE([HAVE_FBSDID_MACRO], [1], MWL>: [Define to 1 if you have the __FBSDID macro.])]) MWL>: MWL>: I can probably improve a bit the queue.h check using what you wrote MWL>: above and AC_PREPROC_IFELSE(). MWL> MWL>The alternative to uglifying the make sources with #ifdefs would be to MWL>just always use the compat includes when building... No autoconf MWL>needed, and minimal changes to the base make, if any.
Yes, please, please don't put #ifdefs into make. It took months to get rid of the cruft that was there and to make it at least somewhat readable. A single compat.h or whatever header file plus, maybe a compat.c file should be sufficient. They can, of course, contain ifdefs. Just include compat.h in all make's c-files. harti _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
