* m4/log2-ieee.m4: New file.
* m4/log2.m4 (gl_FUNC_LOG2): If gl_FUNC_LOG2_IEEE is present, test
whether log2 works with a minus zero argument. Replace it if not.
* modules/log2-ieee (Files): Add m4/log2-ieee.m4.
(configure.ac): Invoke gl_FUNC_LOG2_IEEE.
* doc/posix-functions/log2.texi: Mention the log2-ieee module.
2012-03-11 Bruno Haible <bruno@clisp.org>
+ log2-ieee: Work around test failure on NetBSD 5.1 and Solaris 10.
+ * m4/log2-ieee.m4: New file.
+ * m4/log2.m4 (gl_FUNC_LOG2): If gl_FUNC_LOG2_IEEE is present, test
+ whether log2 works with a minus zero argument. Replace it if not.
+ * modules/log2-ieee (Files): Add m4/log2-ieee.m4.
+ (configure.ac): Invoke gl_FUNC_LOG2_IEEE.
+ * doc/posix-functions/log2.texi: Mention the log2-ieee module.
+
Tests for module 'log2l-ieee'.
* modules/log2l-ieee-tests: New file.
* tests/test-log2l-ieee.c: New file.
POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/log2.html}
-Gnulib module: log2
+Gnulib module: log2 or log2-ieee
-Portability problems fixed by Gnulib:
+Portability problems fixed by either Gnulib module @code{log2} or @code{log2-ieee}:
@itemize
@item
This function is missing on some platforms:
Cygwin 1.7.9.
@end itemize
+Portability problems fixed by Gnulib module @code{log2-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
--- /dev/null
+# log2-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_LOG2 can test whether 'aclocal' has
+dnl found uses of this macro.
+
+AC_DEFUN([gl_FUNC_LOG2_IEEE],
+[
+ m4_divert_text([INIT_PREPARE], [gl_log2_required=ieee])
+ AC_REQUIRE([gl_FUNC_LOG2])
+])
-# log2.m4 serial 1
+# log2.m4 serial 2
dnl Copyright (C) 2010-2012 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
AC_DEFUN([gl_FUNC_LOG2],
[
+ m4_divert_text([DEFAULTS], [gl_log2_required=plain])
AC_REQUIRE([gl_MATH_H_DEFAULTS])
dnl Persuade glibc <math.h> to declare log2().
*yes) ;;
*) REPLACE_LOG2=1 ;;
esac
+
+ m4_ifdef([gl_FUNC_LOG2_IEEE], [
+ if test $gl_log2_required = ieee && test $REPLACE_LOG2 = 0; then
+ AC_CACHE_CHECK([whether log2 works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_log2_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $LOG2_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+#ifndef log2 /* for Cygwin 1.7.x */
+extern
+#ifdef __cplusplus
+"C"
+#endif
+double log2 (double);
+#endif
+/* Compare two numbers with ==.
+ This is a separate function because IRIX 6.5 "cc -O" miscompiles an
+ 'x == x' test. */
+static int
+numeric_equal (double x, double y)
+{
+ return x == y;
+}
+static double dummy (double x) { return 0; }
+int main (int argc, char *argv[])
+{
+ double (*my_log2) (double) = argc ? log2 : dummy;
+ /* Test log2(negative).
+ This test fails on NetBSD 5.1 and Solaris 11 2011-11. */
+ double y = my_log2 (-1.0);
+ if (numeric_equal (y, y))
+ return 1;
+ return 0;
+}
+ ]])],
+ [gl_cv_func_log2_ieee=yes],
+ [gl_cv_func_log2_ieee=no],
+ [gl_cv_func_log2_ieee="guessing no"])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_log2_ieee" in
+ *yes) ;;
+ *) REPLACE_LOG2=1 ;;
+ esac
+ fi
+ ])
else
HAVE_LOG2=0
HAVE_DECL_LOG2=0
log2() function according to ISO C 99 with IEC 60559.
Files:
+m4/log2-ieee.m4
Depends-on:
log2
fpieee
configure.ac:
+gl_FUNC_LOG2_IEEE
Makefile.am: