Content-type: text/html Man page of y0

# y0

Section: Mathematical Library Functions (3M)
Updated: 12 Jul 2006

## NAME

y0, y0f, y0l, y1, y1f, y1l, yn, ynf, ynl - Bessel functions of the second kind

## SYNOPSIS

```c99 [ flag... ] file... -lm [ library... ]
#include <math.h>
```

double y0(double x);

float y0f(float x);

long double y0l(long double x);

double y1(double x);

float y1f(float x);

long double y1l(long double x);

double yn(int n, double x);

float ynf(int n, float x);

long double ynl(int n, long double x);

## DESCRIPTION

These functions compute Bessel functions of x of the second kind of orders 0, 1 and n, respectively.

## RETURN VALUES

Upon successful completion, these functions return the relevant Bessel value of x of the second kind.

If x is NaN, a NaN is returned.

If x is negative, -HUGE_VAL or NaN is returned.

If x is 0.0, -HUGE_VAL is returned.

If the correct result would cause overflow, -HUGE_VAL is returned.

For exceptional cases, matherr(3M) tabulates the values to be returned as specified by SVID3 and XPG3.

## ERRORS

No errors are returned.

## USAGE

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.

## ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

 ATTRIBUTE TYPE ATTRIBUTE VALUE Interface Stability See below. MT-Level MT-Safe

The y0(), y1(), and yn() functions are Standard. The y0f(), y0l(), y1f(), y1l(), ynf(), and ynl() functions are Stable.

isnan(3M), feclearexcept(3M), fetestexcept(3M), j0(3M), math.h(3HEAD), matherr(3M), attributes(5), standards(5)

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUES
ERRORS
USAGE
ATTRIBUTES