# HYPOT

Section: Linux Programmer's Manual (3)
Updated: 2017-09-15
Index

## NAME

hypot, hypotf, hypotl - Euclidean distance function

## SYNOPSIS

`#include <math.h>double hypot(double x, double y);float hypotf(float x, float y);long double hypotl(long double x, long double y);`

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 versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

hypotf(), hypotl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 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 xand 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 a right-angled triangle with sides of length xand y.

If xor yis an infinity, positive infinity is returned.

If xor yis 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
errnois 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 errnofor 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

## CONFORMING TO

C99, POSIX.1-2001, POSIX.1-2008.

The variant returning doublealso conforms to SVr4, 4.3BSD.

cabs(3), sqrt(3)

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
CONFORMING TO