+ m4_ifdef([gl_FUNC_HYPOTF_IEEE], [
+ if test $gl_hypotf_required = ieee && test $REPLACE_HYPOTF = 0; then
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether hypotf works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_hypotf_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $HYPOTF_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+/* Compare two numbers with ==.
+ This is a separate function because IRIX 6.5 "cc -O" miscompiles an
+ 'x == x' test. */
+static int
+numeric_equal (float x, float y)
+{
+ return x == y;
+}
+static float dummy (float x, float y) { return 0; }
+float zero;
+float one = 1.0f;
+int main (int argc, char *argv[])
+{
+ float (*my_hypotf) (float, float) = argc ? hypotf : dummy;
+ float f;
+ /* Test hypotf(NaN,Infinity).
+ This test fails on OSF/1 5.1 and native Windows. */
+ f = my_hypotf (zero / zero, one / zero);
+ if (!numeric_equal (f, f))
+ return 1;
+ return 0;
+}
+ ]])],
+ [gl_cv_func_hypotf_ieee=yes],
+ [gl_cv_func_hypotf_ieee=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_hypotf_ieee="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_hypotf_ieee="guessing no" ;;
+ esac
+ ])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_hypotf_ieee" in
+ *yes) ;;
+ *) REPLACE_HYPOTF=1 ;;
+ esac
+ fi
+ ])