1/* Copyright (C) 2011-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <fenv.h>
19#include <math.h>
20#include <math_private.h>
21#include <math-svid-compat.h>
22#include <libm-alias-double.h>
23
24
25#if LIBM_SVID_COMPAT && (SHLIB_COMPAT (libm, GLIBC_2_0, GLIBC_2_29) \
26 || defined NO_LONG_DOUBLE \
27 || defined LONG_DOUBLE_COMPAT)
28/* wrapper log(x) */
29double
30__log_compat (double x)
31{
32 if (__builtin_expect (islessequal (x, 0.0), 0) && _LIB_VERSION != _IEEE_)
33 {
34 if (x == 0.0)
35 {
36 __feraiseexcept (FE_DIVBYZERO);
37 return __kernel_standard (x, x, 16); /* log(0) */
38 }
39 else
40 {
41 __feraiseexcept (FE_INVALID);
42 return __kernel_standard (x, x, 17); /* log(x<0) */
43 }
44 }
45
46 return __ieee754_log (x);
47}
48# if SHLIB_COMPAT (libm, GLIBC_2_0, GLIBC_2_29)
49compat_symbol (libm, __log_compat, log, GLIBC_2_0);
50# endif
51# ifdef NO_LONG_DOUBLE
52weak_alias (__log_compat, logl)
53# endif
54# ifdef LONG_DOUBLE_COMPAT
55/* Work around gas bug "multiple versions for symbol". */
56weak_alias (__log_compat, __log_compat_alias)
57
58LONG_DOUBLE_COMPAT_CHOOSE_libm_logl (
59 compat_symbol (libm, __log_compat_alias, logl, FIRST_VERSION_libm_logl), );
60# endif
61#endif
62

source code of glibc/math/w_log_compat.c