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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>
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4.\"
5.\" Permission is granted to make and distribute verbatim copies of this
6.\" manual provided the copyright notice and this permission notice are
7.\" preserved on all copies.
8.\"
9.\" Permission is granted to copy and distribute modified versions of this
10.\" manual under the conditions for verbatim copying, provided that the
11.\" entire resulting derived work is distributed under the terms of a
12.\" permission notice identical to this one.
c13182ef 13.\"
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14.\" Since the Linux kernel and libraries are constantly changing, this
15.\" manual page may be incorrect or out-of-date. The author(s) assume no
16.\" responsibility for errors or omissions, or for damages resulting from
17.\" the use of the information contained herein. The author(s) may not
18.\" have taken the same level of care in the production of this manual,
19.\" which is licensed free of charge, as they might when working
20.\" professionally.
c13182ef 21.\"
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22.\" Formatted or processed versions of this manual, if unaccompanied by
23.\" the source, must acknowledge the copyright and authors of this work.
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)
a1949252 32.TH SQRT 3 2008-08-05 "" "Linux Programmer's Manual"
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33.SH NAME
34sqrt, sqrtf, sqrtl \- square root function
35.SH SYNOPSIS
36.nf
37.B #include <math.h>
38.sp
39.BI "double sqrt(double " x );
d39541ec 40.br
fea681da 41.BI "float sqrtf(float " x );
d39541ec 42.br
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43.BI "long double sqrtl(long double " x );
44.fi
45.sp
20c58d70 46Link with \fI\-lm\fP.
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47.sp
48.in -4n
49Feature Test Macro Requirements for glibc (see
50.BR feature_test_macros (7)):
51.in
52.sp
53.ad l
54.BR sqrtf (),
55.BR sqrtl ():
56_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
57.I cc\ -std=c99
58.ad b
fea681da 59.SH DESCRIPTION
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60The
61.BR sqrt ()
62function returns the non-negative square root of \fIx\fP.
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63.SH "RETURN VALUE"
64On success, these functions return the square root of
65.IR x .
66
67If
68.I x
69is a NaN, a NaN is returned.
70
71If
72.I x
73is +0 (\-0), +0 (\-0) is returned.
74
75If
76.I x
77is positive infinity, positive infinity is returned.
78
79If
80.I x
81is less than \-0,
efe294cb 82a domain error occurs,
631c6898 83and a NaN is returned.
fea681da 84.SH ERRORS
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85See
86.BR math_error (7)
87for information on how to determine whether an error has occurred
88when calling these functions.
89.PP
90The following errors can occur:
fea681da 91.TP
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92Domain error: \fIx\fP less than \-0
93.I errno
94is set to
95.BR EDOM .
96An invalid floating-point exception
97.RB ( FE_INVALID )
98is raised.
fea681da 99.SH "CONFORMING TO"
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100C99, POSIX.1-2001.
101The variant returning
102.I double
103also conforms to
68e1685c 104SVr4, 4.3BSD, C89.
fea681da 105.SH "SEE ALSO"
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106.BR cbrt (3),
107.BR csqrt (3),
fea681da 108.BR hypot (3)