.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
.\"     <mtk.manpages@gmail.com>
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
.\" Modified 2002-07-27 by Walter Harms
.\" 	(walter.harms@informatik.uni-oldenburg.de)
.\"
.\" Japanese Version Copyright (c) 1996 Kenji Kajiwara and Kentaro Ogawa
.\"         all rights reserved.
.\" Translated Sat, 13 Jul 1996 17:58:16 JST
.\"         by Kenji Kajiwara and Kentaro Ogawa
.\" Proof Reading: Takashi Yoshino
.\" Updated Tue Aug  5 23:16:48 JST 2003
.\"         by Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2008-09-14, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\"
.TH ATANH 3  2008-08-05 "" "Linux Programmer's Manual"
.SH ̾
atanh, atanhf, atanhl \- жܡinverse hyperbolic tangent˴ؿ
.SH 
.nf
.B #include <math.h>
.sp
.BI "double atanh(double " x );
.br
.BI "float atanhf(float " x );
.br
.BI "long double atanhl(long double " x );
.sp
.fi
\fI\-lm\fP ǥ󥯤롣
.sp
.in -4n
glibc εǽޥ׷
.RB ( feature_test_macros (7)
):
.in
.sp
.ad l
.BR atanh ():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500 || _ISOC99_SOURCE; or
.I cc\ -std=c99
.br
.BR atanhf (),
.BR atanhl ():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
.I cc\ -std=c99
.ad b
.SH 
.BR atanh ()
ؿ \fIx\fP εж (inverse hyperbolic tangent) ׻롣
ʤж (hyperbolic tangent)  \fIx\fP ˤʤ
褦ͤǤ롣
.SH ֤
ȡδؿ
.I x
εжܤ֤

.I x
 NaN ξ硢NaN ֤롣

.I x
 +0 (\-0) ξ硢+0 (\-0) ֤롣

.I x
 +1  \-1 ξ硢
˥顼 (pole error) ȯ
ؿμ˱ơŪ
.BR HUGE_VAL ,
.BR HUGE_VALF ,
.BR HUGE_VALL
줾֤롣

.I x
ͤ 1 礭硢
ΰ襨顼 (domain error) ȯ
NaN ֤롣
.\"
.\" POSIX.1-2001 documents an optional range error for subnormal x;
.\" glibc 2.8 does not do this.
.SH 顼
δؿƤӽФݤ˥顼ȯȽˡˤĤƤξ
.BR math_error (7)
򻲾ȤΤȡ
.PP
ʲΥ顼ȯǽ롣
.TP
ΰ襨顼 (domain error): \fIx\fP  \-1 꾮 +1 礭
.I errno

.B EDOM
ꤵ롣
̵ (invalid) ư㳰
.RB ( FE_INVALID )
夬롣
.TP
˥顼 (pole error): \fIx\fP  +1  \-1
.I errno

.B ERANGE
ꤵ (â֥Хפ⻲)
.\" FIXME . glibc actually gives EDOM for this case
0 ˤ (divide-by-zero) ư㳰
.RB ( FE_DIVBYZERO )
夬롣
.SH 
C99, POSIX.1-2001.
.I double
Ǥδؿ SVr4, 4.3BSD, C89 ˤ򤷤Ƥ롣
.SH Х
˥顼ξˡ
.\"
.\" FIXME . this is as at glibc 2.8; check later if this bug is fixed
.\" This can be seen in sysdeps/ieee754/k_standard.c
.\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6759
.I errno

.B EDOM
ꤵ롣
POSIX.1 Ǥϡ
.B ERANGE
ꤹ٤ȤʤäƤ롣
.SH Ϣ
.BR acosh (3),
.BR asinh (3),
.BR catanh (3),
.BR cosh (3),
.BR sinh (3),
.BR tanh (3)