+
+ m4_ifdef([gl_FUNC_ROUNDF_IEEE], [
+ if test $gl_roundf_required = ieee && test $REPLACE_ROUNDF = 0; then
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether roundf works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_roundf_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $ROUNDF_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+float roundf (float);
+]gl_FLOAT_MINUS_ZERO_CODE[
+]gl_FLOAT_SIGNBIT_CODE[
+static float dummy (float f) { return 0; }
+int main (int argc, char *argv[])
+{
+ float (*my_roundf) (float) = argc ? roundf : dummy;
+ int result = 0;
+ /* Test whether roundf (-0.0f) is -0.0f. */
+ if (signbitf (minus_zerof) && !signbitf (my_roundf (minus_zerof)))
+ result |= 1;
+ /* Test whether roundf (-0.3f) is -0.0f. */
+ if (signbitf (-0.3f) && !signbitf (my_roundf (-0.3f)))
+ result |= 2;
+ return result;
+}
+ ]])],
+ [gl_cv_func_roundf_ieee=yes],
+ [gl_cv_func_roundf_ieee=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_roundf_ieee="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_roundf_ieee="guessing no" ;;
+ esac
+ ])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_roundf_ieee" in
+ *yes) ;;
+ *) REPLACE_ROUNDF=1 ;;
+ esac
+ fi
+ ])
+ else
+ HAVE_ROUNDF=0
+ HAVE_DECL_ROUNDF=0