NEWS.stable: update

[gnulib.git] / m4 / truncl.m4

diff --git a/m4/truncl.m4 b/m4/truncl.m4
index aabd27f..36dd648 100644 (file)
--- a/m4/truncl.m4
+++ b/m4/truncl.m4
@@ -1,12 +1,14 @@
-# truncl.m4 serial 1
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# truncl.m4 serial 6
+dnl Copyright (C) 2007-2008, 2010-2011 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_TRUNCL],
 [
+  m4_divert_text([DEFAULTS], [gl_truncl_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   dnl Persuade glibc <math.h> to declare truncl().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   dnl Test whether truncl() is declared.
@@ -14,35 +16,99 @@ AC_DEFUN([gl_FUNC_TRUNCL],
   if test "$ac_cv_have_decl_truncl" = yes; then
     dnl Test whether truncl() can be used without libm.
     TRUNCL_LIBM=?
-    AC_TRY_LINK([
-       #ifndef __NO_MATH_INLINES
-       # define __NO_MATH_INLINES 1 /* for glibc */
-       #endif
-       #include <math.h>
-       long double x;],
-      [x = truncl(x);],
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#ifndef __NO_MATH_INLINES
+           # define __NO_MATH_INLINES 1 /* for glibc */
+           #endif
+           #include <math.h>
+           long double x;]],
+         [[x = truncl(x);]])],
       [TRUNCL_LIBM=])
     if test "$TRUNCL_LIBM" = "?"; then
       save_LIBS="$LIBS"
       LIBS="$LIBS -lm"
-      AC_TRY_LINK([
-         #ifndef __NO_MATH_INLINES
-         # define __NO_MATH_INLINES 1 /* for glibc */
-         #endif
-         #include <math.h>
-         long double x;],
-        [x = truncl(x);],
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#ifndef __NO_MATH_INLINES
+             # define __NO_MATH_INLINES 1 /* for glibc */
+             #endif
+             #include <math.h>
+             long double x;]],
+           [[x = truncl(x);]])],
         [TRUNCL_LIBM="-lm"])
       LIBS="$save_LIBS"
     fi
     if test "$TRUNCL_LIBM" = "?"; then
       TRUNCL_LIBM=
     fi
+    dnl Test whether truncl() works. It crashes on OSF/1 4.0d.
+    save_LIBS="$LIBS"
+    LIBS="$LIBS $TRUNCL_LIBM"
+    AC_CACHE_CHECK([whether truncl works], [gl_cv_func_truncl_works],
+      [
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <math.h>
+long double x;
+int main()
+{
+  x = truncl (0.0L);
+  return 0;
+}]])],
+          [gl_cv_func_truncl_works=yes],
+          [gl_cv_func_truncl_works=no],
+          [case "$host_os" in
+             osf4*) gl_cv_func_truncl_works="guessing no";;
+             *)     gl_cv_func_truncl_works="guessing yes";;
+           esac
+          ])
+      ])
+    LIBS="$save_LIBS"
+    case "$gl_cv_func_truncl_works" in
+      *yes) ;;
+      *) REPLACE_TRUNCL=1 ;;
+    esac
+    m4_ifdef([gl_FUNC_TRUNCL_IEEE], [
+      if test $gl_truncl_required = ieee && test $REPLACE_TRUNCL = 0; then
+        AC_CACHE_CHECK([whether truncl works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_truncl_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $TRUNCL_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
+]gl_LONG_DOUBLE_SIGNBIT_CODE[
+int main()
+{
+  /* Test whether truncl (-0.3L) is -0.0L.  */
+  if (signbitl (minus_zerol) && !signbitl (truncl (-0.3L)))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_truncl_ieee=yes],
+              [gl_cv_func_truncl_ieee=no],
+              [gl_cv_func_truncl_ieee="guessing no"])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_truncl_ieee" in
+          *yes) ;;
+          *) REPLACE_TRUNCL=1 ;;
+        esac
+      fi
+    ])
   else
     HAVE_DECL_TRUNCL=0
+  fi
+  if test $HAVE_DECL_TRUNCL = 0 || test $REPLACE_TRUNCL = 1; then
     AC_LIBOBJ([truncl])
     TRUNCL_LIBM=
   fi
-  AC_SUBST([HAVE_DECL_TRUNCL])
   AC_SUBST([TRUNCL_LIBM])
 ])