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
