1/* Return cosine of a complex type.
2 Copyright (C) 1997-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <complex.h>
20#include <math.h>
21
22CFLOAT
23M_DECL_FUNC (__cacos) (CFLOAT x)
24{
25 CFLOAT y;
26 CFLOAT res;
27 int rcls = fpclassify (__real__ x);
28 int icls = fpclassify (__imag__ x);
29
30 if (rcls <= FP_INFINITE || icls <= FP_INFINITE
31 || (rcls == FP_ZERO && icls == FP_ZERO))
32 {
33 y = M_SUF (__casin) (x);
34
35 __real__ res = M_MLIT (M_PI_2) - __real__ y;
36 if (__real__ res == 0)
37 __real__ res = 0;
38 __imag__ res = -__imag__ y;
39 }
40 else
41 {
42 __real__ y = -__imag__ x;
43 __imag__ y = __real__ x;
44
45 y = M_SUF (__kernel_casinh) (y, 1);
46
47 __real__ res = __imag__ y;
48 __imag__ res = __real__ y;
49 }
50
51 return res;
52}
53
54declare_mgen_alias (__cacos, cacos);
55

source code of glibc/math/s_cacos_template.c