-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 According to Skip Montanaro on 12/6/2008 9:49 AM: > The Python configure.in file contains a line similar to this: > > AC_CHECK_FUNCS(acosh asinh atanh expm1 finite isinf isnan log1p) > > On Solaris 10 isinf is not detected because the generated conftest.c > doesn't #include <math.h>. Is there a way to tell AC_CHECK_FUNCS > to do that? No - the purpose of AC_CHECK_FUNCS is to check whether the linker can find a function by that name, independently of system headers, so there is no reason to include any system headers. But POSIX states that isinf must be a macro, not a function [1], which means using AC_CHECK_FUNCS for isinf is the wrong check (the macro does not have to expand to a function named isinf, and the test is correctly detecting that there is no isinf function). The correct test, when looking for something that is only guaranteed to be a macro, is to use AC_CHECK_DECLS, which does indeed allow the selection of prerequisite headers. [1] http://www.opengroup.org/onlinepubs/009695399/functions/isinf.html The above test should be rewritten (with proper m4 quoting) as: AC_CHECK_FUNCS([acosh asinh atanh expm1 finite log1p]) AC_CHECK_DECLS([isinf isnan], [], [], [[#include <math.h>]]) then your code adjusted to check for HAVE_DECL_ISINF rather than HAVE_ISINF. But while we are at it, many platforms have a broken isinf and/or isnan, not to mention that the limitation of linking with -lm is annoying when these macros can be portably implemented without needing an extra library. You may be interested in looking into the gnulib isinf and isnan modules. http://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=blob;f=m4/isinf.m4;h=1b9e45a;hb=67461c3 - -- Don't work too hard, make some time for fun as well! Eric Blake ebb9@xxxxxxx -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Cygwin) Comment: Public key at home.comcast.net/~ericblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkk6sUYACgkQ84KuGfSFAYD7pACgyWjGTO1mbWuWnrO38v3xv3rm UBoAnjHHJ5YzbCXnwIeqccJfbAKnPoPv =5xfy -----END PGP SIGNATURE----- _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
