# hypotl (3)

# NAME

hypot, hypotf, hypotl - Euclidean distance function# SYNOPSIS

#include <math.h>

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

*-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 versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

|| _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

|| /* 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

*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 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)