[thirdparty/man-pages.git] / man3 / hypot.3

.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
.\" %%%LICENSE_START(VERBATIM)
.\" 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.\" manual page may be incorrect or out-of-date.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.
.\" %%%LICENSE_END
.\"
.\" 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)
.\"
.TH HYPOT 3 2017-09-15 ""  "Linux Programmer's Manual"
.SH NAME
hypot, hypotf, hypotl \- Euclidean distance function
.SH SYNOPSIS
.nf
.B #include <math.h>
.PP
.BI "double hypot(double " x ", double " y );
.BI "float hypotf(float " x ", float " y );
.BI "long double hypotl(long double " x ", long double " y );
.fi
.PP
Link with \fI\-lm\fP.
.PP
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.PP
.ad l
.BR hypot ():
.RS 4
_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
    || _XOPEN_SOURCE
    || /* Since glibc 2.19: */ _DEFAULT_SOURCE
    || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
.RE
.br
.BR hypotf (),
.BR hypotl ():
.RS 4
_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
    || /* Since glibc 2.19: */ _DEFAULT_SOURCE
    || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
.RE
.ad b
.SH DESCRIPTION
These functions return
.RI sqrt( x * x + y * y ).
This is the length of the hypotenuse of a right-angled triangle
with sides of length
.I x
and
.IR y ,
or the distance of the point
.RI ( x , y )
from the origin.
.PP
The calculation is performed without undue overflow or underflow
during the intermediate steps of the calculation.
.\" e.g., hypot(DBL_MIN, DBL_MIN) does the right thing, as does, say
.\" hypot(DBL_MAX/2.0, DBL_MAX/2.0).
.SH RETURN VALUE
On success, these functions return the length of a right-angled triangle
with sides of length
.I x
and
.IR y .
.PP
If
.I x
or
.I y
is an infinity,
positive infinity is returned.
.PP
If
.I x
or
.I y
is a NaN,
and the other argument is not an infinity,
a NaN is returned.
.PP
If the result overflows,
a range error occurs,
and the functions return
.BR HUGE_VAL ,
.BR HUGE_VALF ,
or
.BR HUGE_VALL ,
respectively.
.PP
If both arguments are subnormal, and the result is subnormal,
.\" Actually, could the result not be subnormal if both arguments
.\" are subnormal?  I think not -- mtk, Jul 2008
a range error occurs,
and the correct result is returned.
.SH ERRORS
See
.BR math_error (7)
for information on how to determine whether an error has occurred
when calling these functions.
.PP
The following errors can occur:
.TP
Range error: result overflow
.I errno
is set to
.BR ERANGE .
An overflow floating-point exception
.RB ( FE_OVERFLOW )
is raised.
.TP
Range error: result underflow
.\" .I errno
.\" is set to
.\" .BR ERANGE .
An underflow floating-point exception
.RB ( FE_UNDERFLOW )
is raised.
.IP
These functions do not set
.IR errno
for this case.
.\" FIXME . Is it intentional that these functions do not set errno?
.\" They do set errno for the overflow case.
.\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6795
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbw27 lb lb
l l l.
Interface	Attribute	Value
T{
.BR hypot (),
.BR hypotf (),
.BR hypotl ()
T}	Thread safety	MT-Safe
.TE
.sp 1
.SH CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
.PP
The variant returning
.I double
also conforms to
SVr4, 4.3BSD.
.SH SEE ALSO
.BR cabs (3),
.BR sqrt (3)
Commit	Line	Data
	1	.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
	2	.\"
	3	.\" %%%LICENSE_START(VERBATIM)
	4	.\" Permission is granted to make and distribute verbatim copies of this
	5	.\" manual provided the copyright notice and this permission notice are
	6	.\" preserved on all copies.
	7	.\"
	8	.\" Permission is granted to copy and distribute modified versions of this
	9	.\" manual under the conditions for verbatim copying, provided that the
	10	.\" entire resulting derived work is distributed under the terms of a
	11	.\" permission notice identical to this one.
	12	.\"
	13	.\" Since the Linux kernel and libraries are constantly changing, this
	14	.\" manual page may be incorrect or out-of-date. The author(s) assume no
	15	.\" responsibility for errors or omissions, or for damages resulting from
	16	.\" the use of the information contained herein. The author(s) may not
	17	.\" have taken the same level of care in the production of this manual,
	18	.\" which is licensed free of charge, as they might when working
	19	.\" professionally.
	20	.\"
	21	.\" Formatted or processed versions of this manual, if unaccompanied by
	22	.\" the source, must acknowledge the copyright and authors of this work.
	23	.\" %%%LICENSE_END
	24	.\"
	25	.\" References consulted:
	26	.\" Linux libc source code
	27	.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
	28	.\" 386BSD man pages
	29	.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
	30	.\" Modified 2002-07-27 by Walter Harms
	31	.\" (walter.harms@informatik.uni-oldenburg.de)
	32	.\"
	33	.TH HYPOT 3 2017-09-15 "" "Linux Programmer's Manual"
	34	.SH NAME
	35	hypot, hypotf, hypotl \- Euclidean distance function
	36	.SH SYNOPSIS
	37	.nf
	38	.B #include <math.h>
	39	.PP
	40	.BI "double hypot(double " x ", double " y );
	41	.BI "float hypotf(float " x ", float " y );
	42	.BI "long double hypotl(long double " x ", long double " y );
	43	.fi
	44	.PP
	45	Link with \fI\-lm\fP.
	46	.PP
	47	.in -4n
	48	Feature Test Macro Requirements for glibc (see
	49	.BR feature_test_macros (7)):
	50	.in
	51	.PP
	52	.ad l
	53	.BR hypot ():
	54	.RS 4
	55	_ISOC99_SOURCE \|\| _POSIX_C_SOURCE\ >=\ 200112L
	56	\|\| _XOPEN_SOURCE
	57	\|\| /* Since glibc 2.19: */ _DEFAULT_SOURCE
	58	\|\| /* Glibc versions <= 2.19: */ _BSD_SOURCE \|\| _SVID_SOURCE
	59	.RE
	60	.br
	61	.BR hypotf (),
	62	.BR hypotl ():
	63	.RS 4
	64	_ISOC99_SOURCE \|\| _POSIX_C_SOURCE\ >=\ 200112L
	65	\|\| /* Since glibc 2.19: */ _DEFAULT_SOURCE
	66	\|\| /* Glibc versions <= 2.19: */ _BSD_SOURCE \|\| _SVID_SOURCE
	67	.RE
	68	.ad b
	69	.SH DESCRIPTION
	70	These functions return
	71	.RI sqrt( x * x + y * y ).
	72	This is the length of the hypotenuse of a right-angled triangle
	73	with sides of length
	74	.I x
	75	and
	76	.IR y ,
	77	or the distance of the point
	78	.RI ( x , y )
	79	from the origin.
	80	.PP
	81	The calculation is performed without undue overflow or underflow
	82	during the intermediate steps of the calculation.
	83	.\" e.g., hypot(DBL_MIN, DBL_MIN) does the right thing, as does, say
	84	.\" hypot(DBL_MAX/2.0, DBL_MAX/2.0).
	85	.SH RETURN VALUE
	86	On success, these functions return the length of a right-angled triangle
	87	with sides of length
	88	.I x
	89	and
	90	.IR y .
	91	.PP
	92	If
	93	.I x
	94	or
	95	.I y
	96	is an infinity,
	97	positive infinity is returned.
	98	.PP
	99	If
	100	.I x
	101	or
	102	.I y
	103	is a NaN,
	104	and the other argument is not an infinity,
	105	a NaN is returned.
	106	.PP
	107	If the result overflows,
	108	a range error occurs,
	109	and the functions return
	110	.BR HUGE_VAL ,
	111	.BR HUGE_VALF ,
	112	or
	113	.BR HUGE_VALL ,
	114	respectively.
	115	.PP
	116	If both arguments are subnormal, and the result is subnormal,
	117	.\" Actually, could the result not be subnormal if both arguments
	118	.\" are subnormal? I think not -- mtk, Jul 2008
	119	a range error occurs,
	120	and the correct result is returned.
	121	.SH ERRORS
	122	See
	123	.BR math_error (7)
	124	for information on how to determine whether an error has occurred
	125	when calling these functions.
	126	.PP
	127	The following errors can occur:
	128	.TP
	129	Range error: result overflow
	130	.I errno
	131	is set to
	132	.BR ERANGE .
	133	An overflow floating-point exception
	134	.RB ( FE_OVERFLOW )
	135	is raised.
	136	.TP
	137	Range error: result underflow
	138	.\" .I errno
	139	.\" is set to
	140	.\" .BR ERANGE .
	141	An underflow floating-point exception
	142	.RB ( FE_UNDERFLOW )
	143	is raised.
	144	.IP
	145	These functions do not set
	146	.IR errno
	147	for this case.
	148	.\" FIXME . Is it intentional that these functions do not set errno?
	149	.\" They do set errno for the overflow case.
	150	.\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6795
	151	.SH ATTRIBUTES
	152	For an explanation of the terms used in this section, see
	153	.BR attributes (7).
	154	.TS
	155	allbox;
	156	lbw27 lb lb
	157	l l l.
	158	Interface Attribute Value
	159	T{
	160	.BR hypot (),
	161	.BR hypotf (),
	162	.BR hypotl ()
	163	T} Thread safety MT-Safe
	164	.TE
	165	.sp 1
	166	.SH CONFORMING TO
	167	C99, POSIX.1-2001, POSIX.1-2008.
	168	.PP
	169	The variant returning
	170	.I double
	171	also conforms to
	172	SVr4, 4.3BSD.
	173	.SH SEE ALSO
	174	.BR cabs (3),
	175	.BR sqrt (3)