changeset 16745:78fe2a20b15c

log10-ieee: Work around test failure on NetBSD 5.1 and Solaris 11. * m4/log10-ieee.m4: New file. * m4/log10.m4 (gl_FUNC_LOG10): If gl_FUNC_LOG10_IEEE is present, test whether log10 works with a negative argument. Replace it if not. * lib/log10.c (log10): For negative arguments, return NaN. * modules/log10-ieee (Files): Add m4/log10-ieee.m4. (configure.ac): Invoke gl_FUNC_LOG10_IEEE. * doc/posix-functions/log10.texi: Mention the log10-ieee module.
author Bruno Haible <bruno@clisp.org>
date Sun, 01 Apr 2012 17:10:01 +0200
parents ca7718d12a97
children 17a69e4fda06
files ChangeLog doc/posix-functions/log10.texi lib/log10.c m4/log10-ieee.m4 m4/log10.m4 modules/log10-ieee
diffstat 6 files changed, 93 insertions(+), 7 deletions(-) [+]
line wrap: on
line diff
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 2012-04-01  Bruno Haible  <bruno@clisp.org>
 
+	log10-ieee: Work around test failure on NetBSD 5.1 and Solaris 11.
+	* m4/log10-ieee.m4: New file.
+	* m4/log10.m4 (gl_FUNC_LOG10): If gl_FUNC_LOG10_IEEE is present, test
+	whether log10 works with a negative argument. Replace it if not.
+	* lib/log10.c (log10): For negative arguments, return NaN.
+	* modules/log10-ieee (Files): Add m4/log10-ieee.m4.
+	(configure.ac): Invoke gl_FUNC_LOG10_IEEE.
+	* doc/posix-functions/log10.texi: Mention the log10-ieee module.
+
 	Tests for module 'log10l-ieee'.
 	* modules/log10l-ieee-tests: New file.
 	* tests/test-log10l-ieee.c: New file.
--- a/doc/posix-functions/log10.texi
+++ b/doc/posix-functions/log10.texi
@@ -4,15 +4,22 @@
 
 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/log10.html}
 
-Gnulib module: log10
+Gnulib module: log10 or log10-ieee
 
-Portability problems fixed by Gnulib:
+Portability problems fixed by either Gnulib module @code{log10} or @code{log10-ieee}:
 @itemize
 @item
 This function returns a wrong value for a minus zero argument on some platforms:
 OSF/1 5.1.
 @end itemize
 
+Portability problems fixed by Gnulib module @code{log10-ieee}:
+@itemize
+@item
+This function returns a wrong value for a negative argument on some platforms:
+NetBSD 5.1, Solaris 11 2011-11.
+@end itemize
+
 Portability problems not fixed by Gnulib:
 @itemize
 @end itemize
--- a/lib/log10.c
+++ b/lib/log10.c
@@ -23,9 +23,16 @@
 log10 (double x)
 #undef log10
 {
-  /* Work around the OSF/1 5.1 bug.  */
-  if (x == 0.0)
-    /* Return -Infinity.  */
-    return -1.0 / 0.0;
+  if (x <= 0.0)
+    {
+      /* Work around the OSF/1 5.1 bug.  */
+      if (x == 0.0)
+        /* Return -Infinity.  */
+        return -1.0 / 0.0;
+      /* Work around the NetBSD 5.1, Solaris 11 2011-11 bug.  */
+      else /* x < 0.0 */
+        /* Return NaN.  */
+        return 0.0 / 0.0;
+    }
   return log10 (x);
 }
new file mode 100644
--- /dev/null
+++ b/m4/log10-ieee.m4
@@ -0,0 +1,15 @@
+# log10-ieee.m4 serial 1
+dnl Copyright (C) 2012 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.
+
+dnl This macro is in a separate file (not in remainder.m4 and not inlined in the
+dnl module description), so that gl_FUNC_LOG10 can test whether 'aclocal' has
+dnl found uses of this macro.
+
+AC_DEFUN([gl_FUNC_LOG10_IEEE],
+[
+  m4_divert_text([INIT_PREPARE], [gl_log10_required=ieee])
+  AC_REQUIRE([gl_FUNC_LOG10])
+])
--- a/m4/log10.m4
+++ b/m4/log10.m4
@@ -1,4 +1,4 @@
-# log10.m4 serial 2
+# log10.m4 serial 3
 dnl Copyright (C) 2011-2012 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -6,6 +6,7 @@
 
 AC_DEFUN([gl_FUNC_LOG10],
 [
+  m4_divert_text([DEFAULTS], [gl_log10_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
 
   dnl Determine LOG10_LIBM.
@@ -19,6 +20,51 @@
     *yes) ;;
     *) REPLACE_LOG10=1 ;;
   esac
+
+  m4_ifdef([gl_FUNC_LOG10_IEEE], [
+    if test $gl_log10_required = ieee && test $REPLACE_LOG10 = 0; then
+      AC_CACHE_CHECK([whether log10 works according to ISO C 99 with IEC 60559],
+        [gl_cv_func_log10_ieee],
+        [
+          save_LIBS="$LIBS"
+          LIBS="$LIBS $LOG10_LIBM"
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+/* Compare two numbers with ==.
+   This is a separate function because IRIX 6.5 "cc -O" miscompiles an
+   'x == x' test.  */
+static int
+numeric_equal (double x, double y)
+{
+  return x == y;
+}
+static double dummy (double x) { return 0; }
+int main (int argc, char *argv[])
+{
+  double (*my_log10) (double) = argc ? log10 : dummy;
+  /* Test log10(negative).
+     This test fails on NetBSD 5.1, Solaris 11 2011-11.  */
+  double y = my_log10 (-1.0);
+  if (numeric_equal (y, y))
+    return 1;
+  return 0;
+}
+            ]])],
+            [gl_cv_func_log10_ieee=yes],
+            [gl_cv_func_log10_ieee=no],
+            [gl_cv_func_log10_ieee="guessing no"])
+          LIBS="$save_LIBS"
+        ])
+      case "$gl_cv_func_log10_ieee" in
+        *yes) ;;
+        *) REPLACE_LOG10=1 ;;
+      esac
+    fi
+  ])
 ])
 
 dnl Test whether log10() works.
--- a/modules/log10-ieee
+++ b/modules/log10-ieee
@@ -2,12 +2,14 @@
 log10() function according to ISO C 99 with IEC 60559.
 
 Files:
+m4/log10-ieee.m4
 
 Depends-on:
 log10
 fpieee
 
 configure.ac:
+gl_FUNC_LOG10_IEEE
 
 Makefile.am: