# SQRT

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

ERRORS

ATTRIBUTES

CONFORMING TO

SEE ALSO

COLOPHON

## NAME

sqrt, sqrtf,
sqrtl − square root function

## SYNOPSIS

**#include
<math.h>**

**double
sqrt(double** *x***); **

float sqrtf(float *x***); **

long double sqrtl(long double *x***);**

Link with
*−lm*.

Feature Test
Macro Requirements for glibc (see
**feature_test_macros**(7)):

**sqrtf**(),
**sqrtl**():

_BSD_SOURCE || _SVID_SOURCE ||
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;

or *cc -std=c99*

## DESCRIPTION

The
**sqrt**() function returns the nonnegative square root
of *x*.

## RETURN VALUE

On success,
these functions return the square root of *x*.

If *x* is
a NaN, a NaN is returned.

If *x* is
+0 (−0), +0 (−0) is returned.

If *x* is
positive infinity, positive infinity is returned.

If *x* is
less than −0, a domain error occurs, and a NaN is
returned.

## ERRORS

See
**math_error**(7) for information on how to determine
whether an error has occurred when calling these
functions.

The following
errors can occur:

Domain error: *x* less than −0

*errno* is set to
**EDOM**. An invalid floating-point exception
(**FE_INVALID**) is raised.

## ATTRIBUTES

For an
explanation of the terms used in this section, see
**attributes**(7).

## CONFORMING TO

C99,
POSIX.1-2001. The variant returning *double* also
conforms to SVr4, 4.3BSD, C89.

## SEE ALSO

**cbrt**(3),
**csqrt**(3), **hypot**(3)

## COLOPHON

This page is
part of release 3.53 of the Linux *man-pages* project.
A description of the project, and information about
reporting bugs, can be found at
http://www.kernel.org/doc/man−pages/.