Final comment: The recreate behaves as I expect if I modify gl_ABSOLUTE_HEADER to use AC_CHECK_HEADERS instead of AC_CHECK_HEADERS_ONCE. My stupidity for not seeing the _ONCE variant buried in there. Sorry. - Rhys On Thu, Aug 14, 2008 at 11:34 AM, Rhys Ulerich <rhys.ulerich@xxxxxxxxx>wrote: > Hi Ralf, > > I got it reproduced. The root cause is a side effect of calling > gl_ABSOLUTE_HEADER ( > http://cvs.savannah.gnu.org/viewvc/*checkout*/gnulib/m4/absolute-header.m4?root=gnulib&content-type=text/plain) > after AC_CHECK_HEADER within my function definition. The expansion of > gl_ABSOLUTE_HEADER causes my function look for the header before I've > modified CPPFLAGS. The, after I modify CPPFLAGS, the cached "no" result is > being used. > > Recreate: > 1. Snag absolute_header.m4 from the link above > 2. Pick your favorite Makefile.am. > 3. Use this configure.ac: > > AC_INIT(recreate, 0.0.1, rhys.ulerich@xxxxxxxxx) >> AM_CONFIG_HEADER(config.h) >> AM_INIT_AUTOMAKE(1.9 -Wall -Werror foreign) >> AC_PREREQ([2.61]) >> >> AC_DEFUN([AX_TRILINOS_BASE],[ >> if test -n "${TRILINOS_HOME}"; >> then >> CPPFLAGS="-I${TRILINOS_HOME}/include $CPPFLAGS" >> fi >> >> AC_MSG_NOTICE([DEBUG: CPPFLAGS=${CPPFLAGS}]) >> AC_CHECK_HEADER([Trilinos_version.h],[found_header=yes]) >> >> if test "$found_header" = yes; then >> gl_ABSOLUTE_HEADER([Trilinos_version.h]) >> AC_DEFINE(HAVE_TRILINOS,1,[Define if Trilinos is available]) >> else >> AC_MSG_ERROR([Trilinos_version.h not found]) >> fi >> ]) >> AX_TRILINOS_BASE >> >> AC_CONFIG_FILES([ >> Makefile >> ]) >> AC_OUTPUT() >> > 4. Invoke 'TRILINOS_HOME=somewhere ./configure' > 5. Look at config.log and observe that the failed Trilinos_version check > did not use the DEBUG: CPPFLAGS=-Isomewhere value displayed in step #4. > > To workaround the issue, choose any of: > > 1. Remove gl_ABSOLUTE_HEADER([Trilinos_version.h]) from > AX_TRILINOS_BASE > 2. Move the gl_ABSOLUTE_HEADER call outside of AX_TRILINOS_BASE into > the toplevel configure.ac. > 3. Move the gl_ABSOLUTE_HEADER call into a separate function that isn't > AX_TRILINOS_BASE. But, you cannot call the new, separate function from > within AX_TRILINOS_BASE otherwise you hit the same issue. > 4. Remove the function AX_TRILINOS_BASE and just dump the function's > code into the main configure.ac file. > > I'll modify my use of gl_ABSOLUTE_HEADER to get past this one. I'll also > email bug-gnulib@xxxxxxx to report it. A note in the gl_ABSOLUTE_HEADER > macro source might save someone else some time. > > Thanks, > Rhys > > > > > > > > > On Thu, Aug 14, 2008 at 2:09 AM, Ralf Wildenhues <Ralf.Wildenhues@xxxxxx>wrote: > >> * Rhys Ulerich wrote on Thu, Aug 14, 2008 at 06:30:50AM CEST: >> > >> > How many chickens must I sacrifice for AC_CHECK_HEADER to notice that >> I've >> > modified CFLAGS/CPPFLAGS within my configure script? >> >> Please show your full configure.ac script, or, even better, a reduced >> one that still exposes this issue. >> >> Since AC_CHECK_HEADER apparently invokes g++, it seems you have an >> AC_LANG([C++]) somewhere, thus CFLAGS won't be used in favor of >> CXXFLAGS. However, CPPFLAGS should still be used. >> >> Cheers, >> Ralf >> > > _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
