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authorTom Lane2006-01-12 19:24:27 +0000
committerTom Lane2006-01-12 19:24:27 +0000
commit1937d8d9efcc0444525a8eb1f6fbc11fddb9512d (patch)
tree4bb8b9972337069d2bf031e7203db1a7251aa0ab /configure.in
parent1fc010cc9695c72fedd45b85ed2d8dadcdc7734a (diff)
Use a more bulletproof test for whether finite() and isinf() are present.
It seems that recent gcc versions can optimize away calls to these functions even when the functions do not exist on the platform, resulting in a bogus positive result. Avoid this by using a non-constant argument and ensuring that the function result is not simply discarded. Per report from François Laupretre.
Diffstat (limited to 'configure.in')
-rw-r--r--configure.in18
1 files changed, 11 insertions, 7 deletions
diff --git a/configure.in b/configure.in
index 94b0a5085d6..8462fffc434 100644
--- a/configure.in
+++ b/configure.in
@@ -1,5 +1,5 @@
dnl Process this file with autoconf to produce a configure script.
-dnl $Header: /cvsroot/pgsql/configure.in,v 1.301.2.18 2006/01/05 03:59:47 momjian Exp $
+dnl $Header: /cvsroot/pgsql/configure.in,v 1.301.2.19 2006/01/12 19:24:26 tgl Exp $
dnl
dnl Developers, please strive to achieve this order:
dnl
@@ -912,12 +912,13 @@ AC_CHECK_FUNCS(vsnprintf, [], pgac_need_repl_snprintf=yes)
AC_CHECK_DECLS([snprintf, vsnprintf])
-# do this one the hard way in case isinf() is a macro
+dnl Cannot use AC_CHECK_FUNC because isinf may be a macro
AC_CACHE_CHECK([for isinf], ac_cv_func_isinf,
-[AC_TRY_LINK(
-[#include <math.h>
+[AC_TRY_LINK([
+#include <math.h>
+double glob_double;
],
-[double x = 0.0; int res = isinf(x);],
+[return isinf(glob_double) ? 0 : 1;],
[ac_cv_func_isinf=yes],
[ac_cv_func_isinf=no])])
@@ -974,8 +975,11 @@ fi
dnl Cannot use AC_CHECK_FUNC because finite may be a macro
AC_MSG_CHECKING(for finite)
-AC_TRY_LINK([#include <math.h>],
- [int dummy=finite(1.0);],
+AC_TRY_LINK([
+#include <math.h>
+double glob_double;
+],
+ [return finite(glob_double) ? 0 : 1;],
[AC_DEFINE(HAVE_FINITE, 1, [Define to 1 if you have finite().])
AC_MSG_RESULT(yes)],
[AC_MSG_RESULT(no)])