-# round.m4 serial 5
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# round.m4 serial 16
+dnl Copyright (C) 2007, 2009-2013 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_ROUND],
[
+ m4_divert_text([DEFAULTS], [gl_round_required=plain])
AC_REQUIRE([gl_MATH_H_DEFAULTS])
+
dnl Persuade glibc <math.h> to declare round().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
- AC_CHECK_DECLS([round], , , [#include <math.h>])
- if test "$ac_cv_have_decl_round" = yes; then
- gl_CHECK_MATH_LIB([ROUND_LIBM], [x = round (x);])
- fi
- if test "$ac_cv_have_decl_round" = yes && test "$ROUND_LIBM" != missing; then
+
+ gl_CHECK_MATH_LIB([ROUND_LIBM], [x = round (x);],
+ [extern
+ #ifdef __cplusplus
+ "C"
+ #endif
+ double round (double);
+ ])
+ if test "$ROUND_LIBM" != missing; then
+ HAVE_ROUND=1
+ dnl Also check whether it's declared.
+ dnl IRIX 6.5 has round() in libm but doesn't declare it in <math.h>.
+ AC_CHECK_DECLS([round], , [HAVE_DECL_ROUND=0], [[#include <math.h>]])
+
dnl Test whether round() produces correct results. On NetBSD 3.0, for
dnl x = 1/2 - 2^-54, the system's round() returns a wrong result.
AC_REQUIRE([AC_PROG_CC])
[
save_LIBS="$LIBS"
LIBS="$LIBS $ROUND_LIBM"
- AC_TRY_RUN([
+ AC_RUN_IFELSE([AC_LANG_SOURCE([[
#include <float.h>
#include <math.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+double round (double);
+#ifdef _MSC_VER
+# pragma fenv_access (off)
+#endif
int main()
{
/* 2^DBL_MANT_DIG. */
* (double) (1U << ((DBL_MANT_DIG + 4) / 5));
volatile double x = 0.5 - 0.5 / TWO_MANT_DIG;
exit (x < 0.5 && round (x) != 0.0);
-}], [gl_cv_func_round_works=yes], [gl_cv_func_round_works=no],
+}]])], [gl_cv_func_round_works=yes], [gl_cv_func_round_works=no],
[case "$host_os" in
- netbsd*) gl_cv_func_round_works="guessing no";;
- *) gl_cv_func_round_works="guessing yes";;
+ netbsd* | aix*) gl_cv_func_round_works="guessing no";;
+ *) gl_cv_func_round_works="guessing yes";;
esac
])
LIBS="$save_LIBS"
])
case "$gl_cv_func_round_works" in
- *no) ROUND_LIBM=missing ;;
+ *no) REPLACE_ROUND=1 ;;
esac
+
+ 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
fi
- if test "$ac_cv_have_decl_round" != yes || test "$ROUND_LIBM" = missing; then
- REPLACE_ROUND=1
- AC_LIBOBJ([round])
+ if test $HAVE_ROUND = 0 || test $REPLACE_ROUND = 1; then
+ dnl Find libraries needed to link lib/round.c.
gl_FUNC_FLOOR_LIBS
gl_FUNC_CEIL_LIBS
- ROUND_LIBM="$FLOOR_LIBM $CEIL_LIBM"
+ ROUND_LIBM=
+ dnl Append $FLOOR_LIBM to ROUND_LIBM, avoiding gratuitous duplicates.
+ case " $ROUND_LIBM " in
+ *" $FLOOR_LIBM "*) ;;
+ *) ROUND_LIBM="$ROUND_LIBM $FLOOR_LIBM" ;;
+ esac
+ dnl Append $CEIL_LIBM to ROUND_LIBM, avoiding gratuitous duplicates.
+ case " $ROUND_LIBM " in
+ *" $CEIL_LIBM "*) ;;
+ *) ROUND_LIBM="$ROUND_LIBM $CEIL_LIBM" ;;
+ esac
fi
AC_SUBST([ROUND_LIBM])
])