+ if test $gl_cv_func_modfl_no_libm = yes \
+ || test $gl_cv_func_modfl_in_libm = yes; then
+ :
+ m4_ifdef([gl_FUNC_MODFL_IEEE], [
+ if test $gl_modfl_required = ieee && test $REPLACE_MODFL = 0; then
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether modfl works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_modfl_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $MODFL_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
+]gl_LONG_DOUBLE_SIGNBIT_CODE[
+/* Compare two numbers with ==.
+ This is a separate function because IRIX 6.5 "cc -O" miscompiles an
+ 'x == x' test. */
+static int
+numeric_equal (long double x, long double y)
+{
+ return x == y;
+}
+static long double dummy (long double x, long double *iptr) { return 0; }
+long double zero;
+long double minus_one = - 1.0L;
+int main (int argc, char *argv[])
+{
+ long double (*my_modfl) (long double, long double *) = argc ? modfl : dummy;
+ long double i;
+ long double f;
+ /* Test modfl(-Inf,...).
+ This test fails on IRIX 6.5, OSF/1 5.1, mingw. */
+ f = my_modfl (minus_one / zero, &i);
+ if (!(f == 0.0L) || (signbitl (minus_zerol) && !signbitl (f)))
+ return 1;
+ return 0;
+}
+ ]])],
+ [gl_cv_func_modfl_ieee=yes],
+ [gl_cv_func_modfl_ieee=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_modfl_ieee="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_modfl_ieee="guessing no" ;;
+ esac
+ ])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_modfl_ieee" in
+ *yes) ;;
+ *) REPLACE_MODFL=1 ;;
+ esac
+ fi
+ ])
+ else