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fea681da | 1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
769cb8d5 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 | .\" |
fea681da MK |
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16 | .\" manual page may be incorrect or out-of-date.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 2002-07-27 by Walter Harms | |
33 | .\" (walter.harms@informatik.uni-oldenburg.de) | |
34 | .\" | |
4b8c67d9 | 35 | .TH TAN 3 2017-09-15 "" "Linux Programmer's Manual" |
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36 | .SH NAME |
37 | tan, tanf, tanl \- tangent function | |
38 | .SH SYNOPSIS | |
39 | .nf | |
40 | .B #include <math.h> | |
68e4db0a | 41 | .PP |
fea681da | 42 | .BI "double tan(double " x ); |
fea681da | 43 | .BI "float tanf(float " x ); |
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44 | .BI "long double tanl(long double " x ); |
45 | .fi | |
68e4db0a | 46 | .PP |
20c58d70 | 47 | Link with \fI\-lm\fP. |
68e4db0a | 48 | .PP |
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49 | .in -4n |
50 | Feature Test Macro Requirements for glibc (see | |
51 | .BR feature_test_macros (7)): | |
52 | .in | |
68e4db0a | 53 | .PP |
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54 | .ad l |
55 | .BR tanf (), | |
56 | .BR tanl (): | |
b90c43a8 | 57 | .RS 4 |
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58 | _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L |
59 | || /* Since glibc 2.19: */ _DEFAULT_SOURCE | |
60 | || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE | |
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61 | .RE |
62 | .ad | |
fea681da | 63 | .SH DESCRIPTION |
5600f73a | 64 | These functions return the tangent of |
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65 | .IR x , |
66 | where | |
67 | .I x | |
68 | is | |
fea681da | 69 | given in radians. |
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70 | .SH RETURN VALUE |
71 | On success, these functions return the tangent of | |
72 | .IR x . | |
847e0d88 | 73 | .PP |
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74 | If |
75 | .I x | |
76 | is a NaN, a NaN is returned. | |
847e0d88 | 77 | .PP |
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78 | If |
79 | .I x | |
80 | is positive infinity or negative infinity, | |
efe294cb | 81 | a domain error occurs, |
769cb8d5 | 82 | and a NaN is returned. |
847e0d88 | 83 | .PP |
769cb8d5 | 84 | If the correct result would overflow, |
efe294cb | 85 | a range error occurs, |
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86 | and the functions return |
87 | .BR HUGE_VAL , | |
88 | .BR HUGE_VALF , | |
89 | or | |
90 | .BR HUGE_VALL , | |
91 | respectively, with the mathematically correct sign. | |
92 | .\" I think overflow can't occur, because the closest floating-point | |
93 | .\" representation of pi/2 is still not close enough to pi/2 to | |
94 | .\" produce a large enough value to overflow. | |
95 | .\" Testing certainly seems to bear this out. -- mtk, Jul 08 | |
96 | .\" | |
97 | .\" POSIX.1 allows an optional underflow error; | |
98 | .\" glibc 2.8 doesn't do this | |
99 | .\" POSIX.1 an optional range error for subnormal x; | |
100 | .\" glibc 2.8 doesn't do this | |
101 | .SH ERRORS | |
102 | See | |
103 | .BR math_error (7) | |
104 | for information on how to determine whether an error has occurred | |
105 | when calling these functions. | |
106 | .PP | |
107 | The following errors can occur: | |
108 | .TP | |
109 | Domain error: \fIx\fP is an infinity | |
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110 | .I errno |
111 | is set to | |
112 | .BR EDOM | |
113 | (but see BUGS). | |
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114 | An invalid floating-point exception |
115 | .RB ( FE_INVALID ) | |
116 | is raised. | |
117 | .TP | |
118 | Range error: result overflow | |
119 | .\" Unable to test this case, since the best approximation of | |
120 | .\" pi/2 in double precision only yields a tan() value of 1.633e16. | |
121 | .\" .I errno | |
122 | .\" is set to | |
123 | .\" .BR ERANGE . | |
124 | An overflow floating-point exception | |
125 | .RB ( FE_OVERFLOW ) | |
126 | is raised. | |
7501f871 | 127 | .SH ATTRIBUTES |
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128 | For an explanation of the terms used in this section, see |
129 | .BR attributes (7). | |
130 | .TS | |
131 | allbox; | |
132 | lbw21 lb lb | |
133 | l l l. | |
134 | Interface Attribute Value | |
135 | T{ | |
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136 | .BR tan (), |
137 | .BR tanf (), | |
7501f871 | 138 | .BR tanl () |
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139 | T} Thread safety MT-Safe |
140 | .TE | |
47297adb | 141 | .SH CONFORMING TO |
9a74e018 | 142 | C99, POSIX.1-2001, POSIX.1-2008. |
847e0d88 | 143 | .PP |
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144 | The variant returning |
145 | .I double | |
146 | also conforms to | |
68e1685c | 147 | SVr4, 4.3BSD, C89. |
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148 | .SH BUGS |
149 | Before version 2.10, the glibc implementation did not set | |
150 | .\" http://sourceware.org/bugzilla/show_bug.cgi?id=6782 | |
151 | .I errno | |
152 | to | |
153 | .B EDOM | |
154 | when a domain error occurred. | |
47297adb | 155 | .SH SEE ALSO |
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156 | .BR acos (3), |
157 | .BR asin (3), | |
158 | .BR atan (3), | |
159 | .BR atan2 (3), | |
160 | .BR cos (3), | |
36268806 | 161 | .BR ctan (3), |
fea681da | 162 | .BR sin (3) |