hypot(3) Library Functions Manual hypot(3)

# NAME¶

hypot, hypotf, hypotl - Euclidean distance function

# LIBRARY¶

Math library (libm, -lm)

# 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 <= 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:

errno is set to ERANGE. An overflow floating-point exception (FE_OVERFLOW) is raised.
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¶

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

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