From: Bruno Haible Date: Sun, 11 Mar 2012 21:12:34 +0000 (+0100) Subject: log2-ieee: Work around test failure on NetBSD 5.1 and Solaris 10. X-Git-Tag: v0.1~838 X-Git-Url: http://erislabs.net/gitweb/?p=gnulib.git;a=commitdiff_plain;h=6bf08d5f7926a6e7d4f851bed1d4b63872a9ed2a 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. --- diff --git a/ChangeLog b/ChangeLog index ec407ee89..e4963bd2d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,13 @@ 2012-03-11 Bruno Haible + 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. diff --git a/doc/posix-functions/log2.texi b/doc/posix-functions/log2.texi index d7037afd0..c943238d4 100644 --- a/doc/posix-functions/log2.texi +++ b/doc/posix-functions/log2.texi @@ -4,9 +4,9 @@ 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: @@ -26,6 +26,13 @@ This function returns slightly wrong values for exact powers of 2 on some platfo 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 diff --git a/m4/log2-ieee.m4 b/m4/log2-ieee.m4 new file mode 100644 index 000000000..6deb26ae7 --- /dev/null +++ b/m4/log2-ieee.m4 @@ -0,0 +1,15 @@ +# 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]) +]) diff --git a/m4/log2.m4 b/m4/log2.m4 index f8ef24bdd..48d0838ce 100644 --- a/m4/log2.m4 +++ b/m4/log2.m4 @@ -1,4 +1,4 @@ -# 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, @@ -6,6 +6,7 @@ dnl with or without modifications, as long as this notice is preserved. AC_DEFUN([gl_FUNC_LOG2], [ + m4_divert_text([DEFAULTS], [gl_log2_required=plain]) AC_REQUIRE([gl_MATH_H_DEFAULTS]) dnl Persuade glibc to declare log2(). @@ -33,6 +34,58 @@ AC_DEFUN([gl_FUNC_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 $LOG2_LIBM" + AC_RUN_IFELSE( + [AC_LANG_SOURCE([[ +#ifndef __NO_MATH_INLINES +# define __NO_MATH_INLINES 1 /* for glibc */ +#endif +#include +#ifndef log2 /* for Cygwin 1.7.x */ +extern +#ifdef __cplusplus +"C" +#endif +double log2 (double); +#endif +/* Compare two numbers with ==. + This is a separate function because IRIX 6.5 "cc -O" miscompiles an + 'x == x' test. */ +static int +numeric_equal (double x, double y) +{ + return x == y; +} +static double dummy (double x) { return 0; } +int main (int argc, char *argv[]) +{ + double (*my_log2) (double) = argc ? log2 : dummy; + /* Test log2(negative). + This test fails on NetBSD 5.1 and Solaris 11 2011-11. */ + double y = my_log2 (-1.0); + if (numeric_equal (y, y)) + return 1; + return 0; +} + ]])], + [gl_cv_func_log2_ieee=yes], + [gl_cv_func_log2_ieee=no], + [gl_cv_func_log2_ieee="guessing no"]) + LIBS="$save_LIBS" + ]) + case "$gl_cv_func_log2_ieee" in + *yes) ;; + *) REPLACE_LOG2=1 ;; + esac + fi + ]) else HAVE_LOG2=0 HAVE_DECL_LOG2=0 diff --git a/modules/log2-ieee b/modules/log2-ieee index a3755347f..80b042e6d 100644 --- a/modules/log2-ieee +++ b/modules/log2-ieee @@ -2,12 +2,14 @@ Description: 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: