Y0(3M) Mathematical Library Functions Y0(3M)

# 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(7) 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.