1 '\" te 2 .\" Copyright (c) 2001, the Institute of Electrical and Electronics Engineers, Inc. and The Open Group. All Rights Reserved. 3 .\" Copyright (c) 1992, X/Open Company Limited. All Rights Reserved. 4 .\" Copyright (c) 1983 Regents of the University of California. All rights reserved. The Berkeley software License Agreement specifies the terms and conditions for redistribution. 5 .\" Portions Copyright (c) 2002, Sun Microsystems, Inc. All Rights Reserved. 6 .\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at 7 .\" http://www.opengroup.org/bookstore/. 8 .\" The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html. 9 .\" This notice shall appear on any product containing this material. 10 .TH acosh 3M "12 Jul 2006" "SunOS 5.11" "Mathematical Library Functions" 11 .SH NAME 12 acosh, acoshf, acoshl \- inverse hyperbolic cosine functions 13 .SH SYNOPSIS 14 .LP 15 .nf 16 c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ] 17 #include <math.h> 18 19 \fBdouble\fR \fBacosh\fR(\fBdouble\fR \fIx\fR); 20 .fi 21 22 .LP 23 .nf 24 \fBfloat\fR \fBacoshf\fR(\fBfloat\fR \fIx\fR); 25 .fi 26 27 .LP 28 .nf 29 \fBlong double\fR \fBacoshl\fR(\fBlong double\fR \fIx\fR); 30 .fi 31 32 .SH DESCRIPTION 33 .sp 34 .LP 35 These functions compute the inverse hyperbolic cosine of their argument 36 \fIx\fR. 37 .SH RETURN VALUES 38 .sp 39 .LP 40 Upon successful completion, these functions return the inverse hyperbolic 41 cosine of their argument. 42 .sp 43 .LP 44 For finite values of \fIx\fR < 1, a domain error occurs and NaN is returned. 45 .sp 46 .LP 47 If \fIx\fR is NaN, NaN is returned. 48 .sp 49 .LP 50 If \fIx\fR is +1, +0 is returned. 51 .sp 52 .LP 53 If \fIx\fR is +Inf, +Inf is returned. 54 .sp 55 .LP 56 If \fIx\fR is \(miInf, a domain error occurs and NaN is returned. 57 .sp 58 .LP 59 For exceptional cases, \fBmatherr\fR(3M) tabulates the values to be returned by 60 \fBacosh()\fR as specified by SVID3 and XPG3. 61 .SH ERRORS 62 .sp 63 .LP 64 These functions will fail if: 65 .sp 66 .ne 2 67 .mk 68 .na 69 \fBDomain Error\fR 70 .ad 71 .RS 16n 72 .rt 73 The \fIx\fR argument is finite and less than 1.0, or is \(miInf. 74 .sp 75 If the integer expression (\fBmath_errhandling\fR & \fBMATH_ERREXCEPT\fR) is 76 non-zero, the invalid floating-point exception is raised. 77 .sp 78 The \fBacosh()\fR function sets \fBerrno\fR to \fBEDOM\fR if \fIx\fR is less 79 than 1.0. 80 .RE 81 82 .SH USAGE 83 .sp 84 .LP 85 An application wanting to check for exceptions should call 86 \fBfeclearexcept\fR(\fBFE_ALL_EXCEPT\fR) before calling these functions. On 87 return, if \fBfetestexcept\fR(\fBFE_INVALID\fR | \fBFE_DIVBYZERO\fR | 88 \fBFE_OVERFLOW\fR | \fBFE_UNDERFLOW\fR) is non-zero, an exception has been 89 raised. An application should either examine the return value or check the 90 floating point exception flags to detect exceptions. 91 .sp 92 .LP 93 An application can also set \fBerrno\fR to 0 before calling \fBacosh()\fR. On 94 return, if \fBerrno\fR is non-zero, an error has occurred. The \fBacoshf()\fR 95 and \fBacoshl()\fR functions do not set \fBerrno\fR. 96 .SH ATTRIBUTES 97 .sp 98 .LP 99 See \fBattributes\fR(5) for descriptions of the following attributes: 100 .sp 101 102 .sp 103 .TS 104 tab() box; 105 cw(2.75i) |cw(2.75i) 106 lw(2.75i) |lw(2.75i) 107 . 108 ATTRIBUTE TYPEATTRIBUTE VALUE 109 _ 110 Interface StabilityStandard 111 _ 112 MT-LevelMT-Safe 113 .TE 114 115 .SH SEE ALSO 116 .sp 117 .LP 118 \fBcosh\fR(3M), \fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M), 119 \fBmath.h\fR(3HEAD), \fBmatherr\fR(3M), \fBattributes\fR(5), \fBstandards\fR(5)