+
+ gl_CHECK_MATH_LIB([ROUNDL_LIBM], [x = roundl (x);],
+ [extern
+ #ifdef __cplusplus
+ "C"
+ #endif
+ long double roundl (long double);
+ ])
+ if test "$ROUNDL_LIBM" != missing; then
+ HAVE_ROUNDL=1
+ dnl Also check whether it's declared.
+ dnl IRIX 6.5 has roundl() in libm but doesn't declare it in <math.h>.
+ AC_CHECK_DECLS([roundl], , [HAVE_DECL_ROUNDL=0], [[#include <math.h>]])
+
+ m4_ifdef([gl_FUNC_ROUNDL_IEEE], [
+ if test $gl_roundl_required = ieee && test $REPLACE_ROUNDL = 0; then
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether roundl works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_roundl_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $ROUNDL_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+long double roundl (long double);
+]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
+]gl_LONG_DOUBLE_SIGNBIT_CODE[
+static long double dummy (long double f) { return 0; }
+int main (int argc, char *argv[])
+{
+ long double (*my_roundl) (long double) = argc ? roundl : dummy;
+ int result = 0;
+ /* Test whether roundl (-0.0L) is -0.0L. */
+ if (signbitl (minus_zerol) && !signbitl (my_roundl (minus_zerol)))
+ result |= 1;
+ /* Test whether roundl (-0.3L) is -0.0L. */
+ if (signbitl (-0.3L) && !signbitl (my_roundl (-0.3L)))
+ result |= 2;
+ return result;
+}
+ ]])],
+ [gl_cv_func_roundl_ieee=yes],
+ [gl_cv_func_roundl_ieee=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_roundl_ieee="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_roundl_ieee="guessing no" ;;
+ esac
+ ])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_roundl_ieee" in
+ *yes) ;;
+ *) REPLACE_ROUNDL=1 ;;
+ esac
+ fi
+ ])
+ else
+ HAVE_ROUNDL=0
+ HAVE_DECL_ROUNDL=0