On 01/22/2011 07:08 PM, Paul Eggert wrote: > To do this, one way to would be to follow the example of > > +# gl_ASSERT_NO_GNULIB_POSIXCHECK > +# asserts that there will never be a need to #define GNULIB_POSIXCHECK. > +# and thereby enables an optimization of configure and config.h. > +# Used by Emacs. > +AC_DEFUN([gl_ASSERT_NO_GNULIB_POSIXCHECK], > +[ > + dnl Override gl_WARN_ON_USE_PREPARE. > + AC_DEFUN([gl_WARN_ON_USE_PREPARE], []) > +])
Yes, this works for me, and I actually would use it in other projects (a developer can temporarily comment out the line, use the POSIX_CHECK features, then recomment it so that ordinary users don't pay the penalty for checking for declarations when they aren't going to use POSIX_CHECK). > Another possibility would be to remove all the HAVE_RAW_DECL_* > symbols, and remove gl_WARN_ON_USE_PREPARE entirely, and replace all > .h code that looks like this: No. That would cause compilation failures. > > #elif defined GNULIB_POSIXCHECK > # undef chown > # if HAVE_RAW_DECL_CHOWN > _GL_WARN_ON_USE (chown, "chown fails to follow symlinks on some systems and > " > "doesn't treat a uid or gid of -1 on some systems - " > "use gnulib module chown for portability"); _GL_WARN_ON_USE _only_ works if a function is already declared (since it uses __typeof__(function) to append the gcc warning attribute). If the function is not declared, life is fine without needing _GL_WARN_ON_USE in the first place (the portability issue would have been detected by the compilation failure when developing on a platform that lacks the function). But it is when the function is declared, but the gnulib version not in use, where you want POSIX_CHECK to issue the warning. > The above analysis suggest that the latter approach is better. > I'd appreciate a review of it, along with any further suggestions > for improvement. I'm only in favor of the former approach, not the latter. -- Eric Blake ebl...@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org
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