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fea681da | 1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
e279ffc3 MK |
2 | .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk |
3 | .\" <mtk.manpages@gmail.com> | |
fea681da | 4 | .\" |
93015253 | 5 | .\" %%%LICENSE_START(VERBATIM) |
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6 | .\" Permission is granted to make and distribute verbatim copies of this |
7 | .\" manual provided the copyright notice and this permission notice are | |
8 | .\" preserved on all copies. | |
9 | .\" | |
10 | .\" Permission is granted to copy and distribute modified versions of this | |
11 | .\" manual under the conditions for verbatim copying, provided that the | |
12 | .\" entire resulting derived work is distributed under the terms of a | |
13 | .\" permission notice identical to this one. | |
c13182ef | 14 | .\" |
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15 | .\" Since the Linux kernel and libraries are constantly changing, this |
16 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
17 | .\" responsibility for errors or omissions, or for damages resulting from | |
18 | .\" the use of the information contained herein. The author(s) may not | |
19 | .\" have taken the same level of care in the production of this manual, | |
20 | .\" which is licensed free of charge, as they might when working | |
21 | .\" professionally. | |
c13182ef | 22 | .\" |
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23 | .\" Formatted or processed versions of this manual, if unaccompanied by |
24 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 25 | .\" %%%LICENSE_END |
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26 | .\" |
27 | .\" References consulted: | |
28 | .\" Linux libc source code | |
29 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
30 | .\" 386BSD man pages | |
31 | .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) | |
32 | .\" Modified 2002-07-25 by Walter Harms | |
33 | .\" (walter.harms@informatik.uni-oldenburg.de) | |
34 | .\" | |
c73595c2 | 35 | .TH ACOS 3 2015-04-19 "" "Linux Programmer's Manual" |
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36 | .SH NAME |
37 | acos, acosf, acosl \- arc cosine function | |
38 | .SH SYNOPSIS | |
39 | .nf | |
40 | .B #include <math.h> | |
41 | .sp | |
42 | .BI "double acos(double " x ); | |
43 | .BI "float acosf(float " x ); | |
44 | .BI "long double acosl(long double " x ); | |
45 | .fi | |
46 | .sp | |
20c58d70 | 47 | Link with \fI\-lm\fP. |
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48 | .sp |
49 | .in -4n | |
50 | Feature Test Macro Requirements for glibc (see | |
51 | .BR feature_test_macros (7)): | |
52 | .in | |
53 | .sp | |
54 | .ad l | |
55 | .BR acosf (), | |
56 | .BR acosl (): | |
36e93b81 | 57 | .RS 4 |
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58 | _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE || |
59 | _POSIX_C_SOURCE\ >=\ 200112L; | |
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60 | .br |
61 | or | |
e279ffc3 | 62 | .I cc\ -std=c99 |
36e93b81 | 63 | .RE |
e279ffc3 | 64 | .ad b |
fea681da | 65 | .SH DESCRIPTION |
5600f73a | 66 | These functions calculate the arc cosine of |
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67 | .IR x ; |
68 | that is | |
69 | the value whose cosine is | |
70 | .IR x . | |
47297adb | 71 | .SH RETURN VALUE |
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72 | On success, these functions return the arc cosine of |
73 | .IR x | |
74 | in radians; the return value is in the range [0,\ pi]. | |
75 | ||
76 | If | |
77 | .I x | |
78 | is a NaN, a NaN is returned. | |
79 | ||
80 | If | |
81 | .I x | |
82 | is +1, | |
83 | +0 is returned. | |
84 | ||
85 | If | |
86 | .I x | |
87 | is positive infinity or negative infinity, | |
efe294cb | 88 | a domain error occurs, |
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89 | and a NaN is returned. |
90 | ||
91 | If | |
92 | .I x | |
93 | is outside the range [\-1,\ 1], | |
efe294cb | 94 | a domain error occurs, |
e279ffc3 | 95 | and a NaN is returned. |
fea681da | 96 | .SH ERRORS |
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97 | See |
98 | .BR math_error (7) | |
99 | for information on how to determine whether an error has occurred | |
100 | when calling these functions. | |
101 | .PP | |
102 | The following errors can occur: | |
fea681da | 103 | .TP |
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104 | Domain error: \fIx\fP is outside the range [\-1,\ 1] |
105 | .I errno | |
106 | is set to | |
107 | .BR EDOM . | |
108 | An invalid floating-point exception | |
109 | .RB ( FE_INVALID ) | |
110 | is raised. | |
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111 | .SH ATTRIBUTES |
112 | For an explanation of the terms used in this section, see | |
113 | .BR attributes (7). | |
114 | .TS | |
115 | allbox; | |
116 | lbw24 lb lb | |
117 | l l l. | |
118 | Interface Attribute Value | |
119 | T{ | |
120 | .BR acos (), | |
121 | .BR acosf (), | |
122 | .BR acosl () | |
123 | T} Thread safety MT-Safe | |
124 | .TE | |
47297adb | 125 | .SH CONFORMING TO |
9a74e018 | 126 | C99, POSIX.1-2001, POSIX.1-2008. |
e05e3635 | 127 | |
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128 | The variant returning |
129 | .I double | |
130 | also conforms to | |
131 | SVr4, 4.3BSD, C89. | |
47297adb | 132 | .SH SEE ALSO |
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133 | .BR asin (3), |
134 | .BR atan (3), | |
135 | .BR atan2 (3), | |
36268806 | 136 | .BR cacos (3), |
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137 | .BR cos (3), |
138 | .BR sin (3), | |
139 | .BR tan (3) |