Hello Tim, * Tim Post wrote on Thu, Jun 12, 2008 at 06:53:29AM CEST: > > I have noticed that if the CFLAGS environment is not set, @CFLAGS@ is > expanded to -g -O2 Is this expected behavior? Yes, that is documented in <http://www.gnu.org/software/autoconf/manual/html_node/C-Compiler.html>. > Also, I see that AC_PROG_CXX ensures that the compiler actually works, > but AC_PROG_CC doesn't seem to do this. The first macro invoked, of AC_PROG_{CC,CXX,F77,FC} does this. > Is there a default macro to > ensure that gcc actually works with the given CFLAGS setting? I'd like > to be sure that flags I set don't conflict with whatever happens to be > in CFLAGS. Well, if you as a user set './configure CFLAGS=...' then that is not overridden: the user is assumed to be always right. If you as a developer want to modify CFLAGS in configure.ac, then I suggest you do so only if the user hasn't set it. You can find this out with test "${CFLAGS+set}" = set before AC_PROG_CC, and modifying CFLAGS in that case, preferably after the AC_PROG_CC invocation so that you get the -g/-O2 testing done by this macro. To find out whether your flags work you could just try to compile or link a simple test program (see AC_COMPILE_IFELSE). HTH. Cheers, Ralf _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
