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comparison m4/log.m4 @ 16631:45443deebb7d

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log: Work around OSF/1 5.1 bug. * lib/math.in.h (log): New declaration. * lib/log.c: New file. * m4/log.m4 (gl_FUNC_LOG_WORKS): New macro. (gl_FUNC_LOG): Invoke it. Set REPLACE_LOG. * m4/math_h.m4 (gl_MATH_H): Test whether log is declared. (gl_MATH_H_DEFAULTS): Initialize GNULIB_LOG, REPLACE_LOG. * modules/math (Makefile.am): Substitute GNULIB_LOG, REPLACE_LOG. * modules/log (Files): Add lib/log.c. (Depends-on): Add math. (configure.ac): If REPLACE_LOG is 1, compile an override. * tests/test-math-c++.cc: Check the declaration of log. * doc/posix-functions/log.texi: Mention the OSF/1 5.1 problem.
author Bruno Haible <bruno@clisp.org>
date Fri, 09 Mar 2012 23:55:13 +0100
parents 8250f2777afc
children 521c2cde0e31
comparison
equal deleted inserted replaced
16630:1ac24dbbff5a 16631:45443deebb7d
1 # log.m4 serial 1 1 # log.m4 serial 2
2 dnl Copyright (C) 2011-2012 Free Software Foundation, Inc. 2 dnl Copyright (C) 2011-2012 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation 3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it, 4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved. 5 dnl with or without modifications, as long as this notice is preserved.
6 6
7 AC_DEFUN([gl_FUNC_LOG], 7 AC_DEFUN([gl_FUNC_LOG],
8 [ 8 [
9 dnl Determine LOG_LIBM. 9 dnl Determine LOG_LIBM.
10 gl_COMMON_DOUBLE_MATHFUNC([log]) 10 gl_COMMON_DOUBLE_MATHFUNC([log])
11
12 save_LIBS="$LIBS"
13 LIBS="$LIBS $LOG_LIBM"
14 gl_FUNC_LOG_WORKS
15 LIBS="$save_LIBS"
16 case "$gl_cv_func_log_works" in
17 *yes) ;;
18 *) REPLACE_LOG=1 ;;
19 esac
11 ]) 20 ])
21
22 dnl Test whether log() works.
23 dnl On OSF/1 5.1, log(-0.0) is NaN.
24 AC_DEFUN([gl_FUNC_LOG_WORKS],
25 [
26 AC_REQUIRE([AC_PROG_CC])
27 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
28 AC_CACHE_CHECK([whether log works], [gl_cv_func_log_works],
29 [
30 AC_RUN_IFELSE(
31 [AC_LANG_SOURCE([[
32 #include <math.h>
33 volatile double x;
34 double y;
35 int main ()
36 {
37 x = -0.0;
38 y = log (x);
39 if (!(y + y == y))
40 return 1;
41 return 0;
42 }
43 ]])],
44 [gl_cv_func_log_works=yes],
45 [gl_cv_func_log_works=no],
46 [case "$host_os" in
47 osf*) gl_cv_func_log_works="guessing no";;
48 *) gl_cv_func_log_works="guessing yes";;
49 esac
50 ])
51 ])
52 ])