HYPOT(3) | Linux Programmer's Manual | HYPOT(3) |

# NAME

hypot, hypotf, hypotl - Euclidean distance function# SYNOPSIS

#include <math.h>

double hypot(doublex, doubley);float hypotf(floatx, floaty);long double hypotl(long doublex, long doubley);

Link with *-lm*.

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 |

# CONFORMING TO

C99, POSIX.1-2001, POSIX.1-2008.The variant returning *double* also conforms to SVr4,
4.3BSD.

# SEE ALSO

cabs(3), sqrt(3)# COLOPHON

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2021-03-22 |