X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ftruncl.m4;h=c594236afbd504a6810723c7cf336bcd22bcc590;hb=9f60473985e5f20c3efabadf2c1756b5ff560458;hp=0498585b2033a1df69aa736fe914a0fdac099913;hpb=23737e3dd01ef6ac0ae9134300a4c66807ae00d2;p=gnulib.git

diff --git a/m4/truncl.m4 b/m4/truncl.m4
index 0498585b2..c594236af 100644
--- a/m4/truncl.m4
+++ b/m4/truncl.m4
@@ -1,11 +1,12 @@
-# truncl.m4 serial 4
-dnl Copyright (C) 2007-2008, 2010 Free Software Foundation, Inc.
+# truncl.m4 serial 8
+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().
@@ -15,24 +16,26 @@ 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="$save_LIBS"
     fi
@@ -40,31 +43,73 @@ AC_DEFUN([gl_FUNC_TRUNCL],
       TRUNCL_LIBM=
     fi
     dnl Test whether truncl() works. It crashes on OSF/1 4.0d.
+    save_LIBS="$LIBS"
+    LIBS="$LIBS $TRUNCL_LIBM"
     AC_CACHE_CHECK([whether truncl works], [gl_cv_func_truncl_works],
       [
-        AC_TRY_RUN([
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
 #include <math.h>
 long double x;
 int main()
 {
   x = truncl (0.0L);
   return 0;
-}], [gl_cv_func_truncl_works=yes], [gl_cv_func_truncl_works=no],
+}]])],
+          [gl_cv_func_truncl_works=yes],
+          [gl_cv_func_truncl_works=no],
           [case "$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 $TRUNCL_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
+]gl_LONG_DOUBLE_SIGNBIT_CODE[
+static long double dummy (long double f) { return 0; }
+int main (int argc, char *argv[])
+{
+  long double (*my_truncl) (long double) = argc ? truncl : dummy;
+  /* Test whether truncl (-0.3L) is -0.0L.  */
+  if (signbitl (minus_zerol) && !signbitl (my_truncl (-0.3L)))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_truncl_ieee=yes],
+              [gl_cv_func_truncl_ieee=no],
+              [gl_cv_func_truncl_ieee="guessing no"])
+            LIBS="$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])
+    dnl No libraries are needed to link lib/truncl.c.
     TRUNCL_LIBM=
   fi
   AC_SUBST([TRUNCL_LIBM])