+
+ m4_ifdef([gl_FUNC_ROUND_IEEE], [
+ if test $gl_round_required = ieee && test $REPLACE_ROUND = 0; then
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether round works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_round_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $ROUND_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+double round (double);
+]gl_DOUBLE_MINUS_ZERO_CODE[
+]gl_DOUBLE_SIGNBIT_CODE[
+static double dummy (double f) { return 0; }
+int main (int argc, char *argv[])
+{
+ double (*my_round) (double) = argc ? round : dummy;
+ /* Test whether round (-0.0) is -0.0. */
+ if (signbitd (minus_zerod) && !signbitd (my_round (minus_zerod)))
+ return 1;
+ return 0;
+}
+ ]])],
+ [gl_cv_func_round_ieee=yes],
+ [gl_cv_func_round_ieee=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_round_ieee="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_round_ieee="guessing no" ;;
+ esac
+ ])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_round_ieee" in
+ *yes) ;;
+ *) REPLACE_ROUND=1 ;;
+ esac
+ fi
+ ])
+ else
+ HAVE_ROUND=0
+ HAVE_DECL_ROUND=0