### 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; or
*cc -std=c99*

### DESCRIPTION

The
**sqrt**() function returns the non-negative 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.
| |

### CONFORMING TO

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

### SEE ALSO

### COLOPHON

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A description of the project,
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