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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] 12 .TH atanh 3M "12 Jul 2006" "SunOS 5.11" "Mathematical Library Functions" 13 .SH NAME 14 atanh, atanhf, atanhl \- inverse hyperbolic tangent functions 15 .SH SYNOPSIS 16 .LP 17 .nf 18 c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ] 19 #include <math.h> 20 21 \fBdouble\fR \fBatanh\fR(\fBdouble\fR \fIx\fR); 22 .fi 23 24 .LP 25 .nf 26 \fBfloat\fR \fBatanhf\fR(\fBfloat\fR \fIx\fR); 27 .fi 28 29 .LP 30 .nf 31 \fBlong double\fR \fBatanhl\fR(\fBlong double\fR \fIx\fR); 32 .fi 33 34 .SH DESCRIPTION 35 .sp 36 .LP 37 These functions compute the inverse hyperbolic tangent of their argument 38 \fIx\fR. 39 .SH RETURN VALUES 40 .sp 41 .LP 42 Upon successful completion, these functions return the inverse hyperbolic 43 tangent of their argument. 44 .sp 45 .LP 46 If \fIx\fR is \(+-1, a pole error occurs and \fBatanh()\fR, \fBatanhf()\fR, and 47 \fBatanhl()\fR return the value of the macro \fBHUGE_VAL\fR, \fBHUGE_VALF\fR, 48 and \fBHUGE_VALL\fR, respectively, with the same sign as the correct value of 49 the function. 50 .sp 51 .LP 52 For finite |\fIx\fR| > 1, a domain error occurs and a NaN is returned. 53 .sp 54 .LP 55 If \fIx\fR is NaN, NaN is returned. 56 .sp 57 .LP 58 If \fIx\fR is +0, \fIx\fR is returned. 59 .sp 60 .LP 61 If \fIx\fR is +Inf, a domain error occurs and a NaN is returned. 62 .sp 63 .LP 64 For exceptional cases, \fBmatherr\fR(3M) tabulates the values to be returned by 65 \fBatanh()\fR as specified by SVID3 and XPG3. 66 .SH ERRORS 67 .sp 68 .LP 69 These functions will fail if: 70 .sp 71 .ne 2 72 .mk 73 .na 74 \fBDomain Error\fR 75 .ad 76 .RS 16n 77 .rt 78 The \fIx\fR argument is finite and not in the range [-1,1], or is \(+-Inf. 79 .sp 80 If the integer expression (\fBmath_errhandling\fR & \fBMATH_ERREXCEPT\fR) is 81 non-zero, the invalid floating-point exception is raised. 82 .sp 83 The \fBatanh()\fR function sets \fBerrno\fR to \fBEDOM\fR if the absolute value 84 of \fIx\fR is greater than 1.0. 85 .RE 86 87 .sp 88 .ne 2 89 .mk 90 .na 91 \fBPole Error\fR 92 .ad 93 .RS 16n 94 .rt 95 The \fIx\fR argument is \(+-1. 96 .sp 97 If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then 98 the divide-by-zero floating-point exception is raised. 99 .sp 100 The \fBatanh()\fR function sets \fBerrno\fR to \fBERANGE\fR if the absolute 101 value of \fIx\fR is equal to 1.0. 102 .RE 103 104 .SH USAGE 105 .sp 106 .LP 107 An application wanting to check for exceptions should call 108 \fBfeclearexcept\fR(\fBFE_ALL_EXCEPT\fR) before calling these functions. On 109 return, if \fBfetestexcept\fR(\fBFE_INVALID\fR | \fBFE_DIVBYZERO\fR | 110 \fBFE_OVERFLOW\fR | \fBFE_UNDERFLOW\fR) is non-zero, an exception has been 111 raised. An application should either examine the return value or check the 112 floating point exception flags to detect exceptions. 113 .sp 114 .LP 115 An application can also set \fBerrno\fR to 0 before calling \fBatanh()\fR. On 116 return, if \fBerrno\fR is non-zero, an error has occurred. The \fBatanhf()\fR 117 and \fBatanhl()\fR functions do not set \fBerrno\fR. 118 .SH ATTRIBUTES 119 .sp 120 .LP 121 See \fBattributes\fR(5) for descriptions of the following attributes: 122 .sp 123 124 .sp 125 .TS 126 tab() box; 127 cw(2.75i) |cw(2.75i) 128 lw(2.75i) |lw(2.75i) 129 . 130 ATTRIBUTE TYPEATTRIBUTE VALUE 131 _ 132 Interface StabilityStandard 133 _ 134 MT-LevelMT-Safe 135 .TE 136 137 .SH SEE ALSO 138 .sp 139 .LP 140 \fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M), \fBmath.h\fR(3HEAD), 141 \fBmatherr\fR(3M), \fBtanh\fR(3M), \fBattributes\fR(5), \fBstandards\fR(5)