# hypot - Man Page

Euclidean distance function

## Library

Math library (*libm*, *-lm*)

## Synopsis

#include <math.h> double hypot(doublex, doubley); float hypotf(floatx, floaty); long double hypotl(long doublex, long doubley);

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

**hypot**():

_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

**hypotf**(), **hypotl**():

_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

## Description

These functions return sqrt(*x***x*+*y***y*). This is the length of the hypotenuse of a right-angled triangle with sides of length *x* and *y*, or the distance of the point (*x*,*y*) from the origin.

The calculation is performed without undue overflow or underflow during the intermediate steps of the calculation.

## Return Value

On success, these functions return the length of the hypotenuse of a right-angled triangle with sides of length *x* and *y*.

If *x* or *y* is an infinity, positive infinity is returned.

If *x* or *y* is a NaN, and the other argument is not an infinity, a NaN is returned.

If the result overflows, a range error occurs, and the functions return **HUGE_VAL**, **HUGE_VALF**, or **HUGE_VALL**, respectively.

If both arguments are subnormal, and the result is subnormal, a range error occurs, and the correct result 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:

- Range error: result overflow
*errno*is set to**ERANGE**. An overflow floating-point exception (**FE_OVERFLOW**) is raised.- Range error: result underflow
An underflow floating-point exception (

**FE_UNDERFLOW**) is raised.These functions do not set

*errno*for this case.

## Attributes

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

Interface | Attribute | Value |
---|---|---|

hypot(), hypotf(), hypotl() | Thread safety | MT-Safe |

## Standards

C11, POSIX.1-2008.

## History

C99, POSIX.1-2001.

The variant returning *double* also conforms to SVr4, 4.3BSD.

## See Also

## Referenced By

cabs(3), sqrt(3), stress-ng(1).

The man pages hypotf(3) and hypotl(3) are aliases of hypot(3).