projects / thirdparty / man-pages.git / blame
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| fea681da | 1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
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2 | .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk |
| 3 | .\" <mtk.manpages@gmail.com> | |
| fea681da | 4 | .\" |
| 5fbde956 | 5 | .\" SPDX-License-Identifier: Linux-man-pages-copyleft |
| fea681da MK |
6 | .\" |
| 7 | .\" References consulted: | |
| 8 | .\" Linux libc source code | |
| 9 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
| 10 | .\" 386BSD man pages | |
| 11 | .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) | |
| 12 | .\" Modified 2002-07-27 by Walter Harms | |
| 13 | .\" (walter.harms@informatik.uni-oldenburg.de) | |
| 14 | .\" | |
| 1ae6b2c7 | 15 | .TH TANH 3 2021-03-22 GNU "Linux Programmer's Manual" |
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16 | .SH NAME |
| 17 | tanh, tanhf, tanhl \- hyperbolic tangent function | |
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18 | .SH LIBRARY |
| 19 | Math library | |
| 8fc3b2cf | 20 | .RI ( libm ", " \-lm ) |
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21 | .SH SYNOPSIS |
| 22 | .nf | |
| 23 | .B #include <math.h> | |
| 68e4db0a | 24 | .PP |
| fea681da | 25 | .BI "double tanh(double " x ); |
| fea681da | 26 | .BI "float tanhf(float " x ); |
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27 | .BI "long double tanhl(long double " x ); |
| 28 | .fi | |
| 68e4db0a | 29 | .PP |
| d39ad78f | 30 | .RS -4 |
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31 | Feature Test Macro Requirements for glibc (see |
| 32 | .BR feature_test_macros (7)): | |
| d39ad78f | 33 | .RE |
| 68e4db0a | 34 | .PP |
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35 | .BR tanhf (), |
| 36 | .BR tanhl (): | |
| 9d2adbae | 37 | .nf |
| 5c10d2c5 | 38 | _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L |
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39 | || /* Since glibc 2.19: */ _DEFAULT_SOURCE |
| 40 | || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE | |
| 41 | .fi | |
| fea681da | 42 | .SH DESCRIPTION |
| 5600f73a | 43 | These functions return the hyperbolic tangent of |
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44 | .IR x , |
| 45 | which | |
| 658670de | 46 | is defined mathematically as: |
| a2b7a144 | 47 | .PP |
| 658670de | 48 | .nf |
| 658670de | 49 | tanh(x) = sinh(x) / cosh(x) |
| 494fc522 | 50 | .fi |
| 47297adb | 51 | .SH RETURN VALUE |
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52 | On success, these functions return the hyperbolic tangent of |
| 53 | .IR x . | |
| 847e0d88 | 54 | .PP |
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55 | If |
| 56 | .I x | |
| 57 | is a NaN, a NaN is returned. | |
| 847e0d88 | 58 | .PP |
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59 | If |
| 60 | .I x | |
| 61 | is +0 (\-0), +0 (\-0) is returned. | |
| 847e0d88 | 62 | .PP |
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63 | If |
| 64 | .I x | |
| 65 | is positive infinity (negative infinity), | |
| 66 | +1 (\-1) is returned. | |
| 67 | .\" | |
| 385cf745 | 68 | .\" POSIX.1-2001 documents an optional range error (underflow) |
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69 | .\" for subnormal x; |
| 70 | .\" glibc 2.8 does not do this. | |
| 71 | .SH ERRORS | |
| 72 | No errors occur. | |
| 38d62724 | 73 | .SH ATTRIBUTES |
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74 | For an explanation of the terms used in this section, see |
| 75 | .BR attributes (7). | |
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76 | .ad l |
| 77 | .nh | |
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78 | .TS |
| 79 | allbox; | |
| c466875e | 80 | lbx lb lb |
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81 | l l l. |
| 82 | Interface Attribute Value | |
| 83 | T{ | |
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84 | .BR tanh (), |
| 85 | .BR tanhf (), | |
| 38d62724 | 86 | .BR tanhl () |
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87 | T} Thread safety MT-Safe |
| 88 | .TE | |
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89 | .hy |
| 90 | .ad | |
| 91 | .sp 1 | |
| 47297adb | 92 | .SH CONFORMING TO |
| 9a74e018 | 93 | C99, POSIX.1-2001, POSIX.1-2008. |
| 847e0d88 | 94 | .PP |
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95 | The variant returning |
| 96 | .I double | |
| 97 | also conforms to | |
| 68e1685c | 98 | SVr4, 4.3BSD, C89. |
| 47297adb | 99 | .SH SEE ALSO |
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100 | .BR acosh (3), |
| 101 | .BR asinh (3), | |
| 102 | .BR atanh (3), | |
| 103 | .BR cosh (3), | |
| 36268806 | 104 | .BR ctanh (3), |
| fea681da | 105 | .BR sinh (3) |