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1 | # log.m4 serial 4 |
2 | dnl Copyright (C) 2011-2012 Free Software Foundation, Inc. | |
3 | dnl This file is free software; the Free Software Foundation | |
4 | dnl gives unlimited permission to copy and/or distribute it, | |
5 | dnl with or without modifications, as long as this notice is preserved. | |
6 | ||
7 | AC_DEFUN([gl_FUNC_LOG], | |
8 | [ | |
9 | m4_divert_text([DEFAULTS], [gl_log_required=plain]) | |
10 | AC_REQUIRE([gl_MATH_H_DEFAULTS]) | |
11 | ||
12 | dnl Determine LOG_LIBM. | |
13 | gl_COMMON_DOUBLE_MATHFUNC([log]) | |
14 | ||
15 | save_LIBS="$LIBS" | |
16 | LIBS="$LIBS $LOG_LIBM" | |
17 | gl_FUNC_LOG_WORKS | |
18 | LIBS="$save_LIBS" | |
19 | case "$gl_cv_func_log_works" in | |
20 | *yes) ;; | |
21 | *) REPLACE_LOG=1 ;; | |
22 | esac | |
23 | ||
24 | m4_ifdef([gl_FUNC_LOG_IEEE], [ | |
25 | if test $gl_log_required = ieee && test $REPLACE_LOG = 0; then | |
26 | AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles | |
27 | AC_CACHE_CHECK([whether log works according to ISO C 99 with IEC 60559], | |
28 | [gl_cv_func_log_ieee], | |
29 | [ | |
30 | save_LIBS="$LIBS" | |
31 | LIBS="$LIBS $LOG_LIBM" | |
32 | AC_RUN_IFELSE( | |
33 | [AC_LANG_SOURCE([[ | |
34 | #ifndef __NO_MATH_INLINES | |
35 | # define __NO_MATH_INLINES 1 /* for glibc */ | |
36 | #endif | |
37 | #include <math.h> | |
38 | /* Compare two numbers with ==. | |
39 | This is a separate function because IRIX 6.5 "cc -O" miscompiles an | |
40 | 'x == x' test. */ | |
41 | static int | |
42 | numeric_equal (double x, double y) | |
43 | { | |
44 | return x == y; | |
45 | } | |
46 | static double dummy (double x) { return 0; } | |
47 | int main (int argc, char *argv[]) | |
48 | { | |
49 | double (*my_log) (double) = argc ? log : dummy; | |
50 | /* Test log(negative). | |
51 | This test fails on NetBSD 5.1, Solaris 11 2011-11. */ | |
52 | double y = my_log (-1.0); | |
53 | if (numeric_equal (y, y)) | |
54 | return 1; | |
55 | return 0; | |
56 | } | |
57 | ]])], | |
58 | [gl_cv_func_log_ieee=yes], | |
59 | [gl_cv_func_log_ieee=no], | |
60 | [case "$host_os" in | |
61 | # Guess yes on glibc systems. | |
62 | *-gnu*) gl_cv_func_log_ieee="guessing yes" ;; | |
63 | # If we don't know, assume the worst. | |
64 | *) gl_cv_func_log_ieee="guessing no" ;; | |
65 | esac | |
66 | ]) | |
67 | LIBS="$save_LIBS" | |
68 | ]) | |
69 | case "$gl_cv_func_log_ieee" in | |
70 | *yes) ;; | |
71 | *) REPLACE_LOG=1 ;; | |
72 | esac | |
73 | fi | |
74 | ]) | |
75 | ]) | |
76 | ||
77 | dnl Test whether log() works. | |
78 | dnl On OSF/1 5.1, log(-0.0) is NaN. | |
79 | AC_DEFUN([gl_FUNC_LOG_WORKS], | |
80 | [ | |
81 | AC_REQUIRE([AC_PROG_CC]) | |
82 | AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles | |
83 | AC_CACHE_CHECK([whether log works], [gl_cv_func_log_works], | |
84 | [ | |
85 | AC_RUN_IFELSE( | |
86 | [AC_LANG_SOURCE([[ | |
87 | #include <math.h> | |
88 | volatile double x; | |
89 | double y; | |
90 | int main () | |
91 | { | |
92 | x = -0.0; | |
93 | y = log (x); | |
94 | if (!(y + y == y)) | |
95 | return 1; | |
96 | return 0; | |
97 | } | |
98 | ]])], | |
99 | [gl_cv_func_log_works=yes], | |
100 | [gl_cv_func_log_works=no], | |
101 | [case "$host_os" in | |
102 | osf*) gl_cv_func_log_works="guessing no";; | |
103 | *) gl_cv_func_log_works="guessing yes";; | |
104 | esac | |
105 | ]) | |
106 | ]) | |
107 | ]) |