'\" t
.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.TH sqrt 3 (date) "Linux man-pages (unreleased)"
.SH NAME
sqrt, sqrtf, sqrtl \- square root function
.SH LIBRARY
Math library
.RI ( libm ,\~ \-lm )
.SH SYNOPSIS
.nf
.B #include <math.h>
.P
.BI "double sqrt(double " x );
.BI "float sqrtf(float " x );
.BI "long double sqrtl(long double " x );
.fi
.P
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.RE
.P
.BR sqrtf (),
.BR sqrtl ():
.nf
    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
.fi
.SH DESCRIPTION
These functions return the nonnegative square root of
.IR x .
.SH RETURN VALUE
On success, these functions return the square root of
.IR x .
.P
If
.I x
is a NaN, a NaN is returned.
.P
If
.I x
is +0 (\-0), +0 (\-0) is returned.
.P
If
.I x
is positive infinity, positive infinity is returned.
.P
If
.I x
is less than \-0,
a domain error occurs,
and a NaN is returned.
.SH ERRORS
See
.BR math_error (7)
for information on how to determine whether an error has occurred
when calling these functions.
.P
The following errors can occur:
.TP
Domain error: \f[I]x\f[] less than \-0
.I errno
is set to
.BR EDOM .
An invalid floating-point exception
.RB ( FE_INVALID )
is raised.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.na
.nh
.BR sqrt (),
.BR sqrtf (),
.BR sqrtl ()
T}	Thread safety	MT-Safe
.TE
.SH STANDARDS
C11, POSIX.1-2008.
.SH HISTORY
C99, POSIX.1-2001.
.P
The variant returning
.I double
also conforms to
SVr4, 4.3BSD, C89.
.SH SEE ALSO
.BR cbrt (3),
.BR csqrt (3),
.BR hypot (3)