y03p
Bessel functions of the second kind
Usage
#include <math.h>
double y0(double x); double y1(double x); double yn(int n, double x);
Prolog
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
Overview
The y0(), y1(), and yn() functions shall compute Bessel functions of x of the second kind of orders 0, 1, and n, respectively.
An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if errno is non-zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.
Return value
Upon successful completion, these functions shall return the relevant Bessel value of x of the second kind.
If x is NaN, NaN shall be returned.
If the x argument to these functions is negative, -HUGE_VAL or NaN shall be returned, and a domain error may occur.
If x is 0.0, -HUGE_VAL shall be returned and a pole error may occur.
If the correct result would cause underflow, 0.0 shall be returned and a range error may occur.
If the correct result would cause overflow, -HUGE_VAL or 0.0 shall be returned and a range error may occur.
Errors
These functions may fail if:
- Domain Error
-
The value of x is negative.
If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be raised.
- Pole Error
-
The value of x is zero.
If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the divide-by-zero floating-point exception shall be raised.
- Range Error
-
The correct result would cause overflow.
If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception shall be raised.
- Range Error
-
The value of x is too large in magnitude, or the correct result would cause underflow.
If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow floating-point exception shall be raised.
The following sections are informative.
Examples
None.
Application usage
On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.
Rationale
None.
Future directions
None.