Y0Section: Linux Programmer's Manual (3)
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NAMEy0, y0f, y0l, y1, y1f, y1l, yn, ynf, ynl - Bessel functions of the second kind
#include <math.h> double y0(double x);
double y1(double x);
double yn(int n, double x); float y0f(float x);
float y1f(float x);
float ynf(int n, float x); long double y0l(long double x);
long double y1l(long double x);
long double ynl(int n, long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
The y0() and y1() functions return Bessel functions of x of the second kind of orders 0 and 1, respectively. The yn() function returns the Bessel function of x of the second kind of order n.
The value of x must be positive.
RETURN VALUEOn success, these functions return the appropriate Bessel value of the second kind for x.
If x is a NaN, a NaN is returned.
If x is negative, a domain error occurs, and the functions return -HUGE_VAL, -HUGE_VALF, or -HUGE_VALL, respectively. (POSIX.1-2001 also allows a NaN return for this case.)
If x is 0.0, a pole error occurs, and the functions return -HUGE_VAL, -HUGE_VALF, or -HUGE_VALL, respectively.
If the result underflows, a range error occurs, and the functions return 0.0
ERRORSSee math_error(7) for information on how to determine whether an error has occurred when calling these functions.
The following errors can occur:
- Domain error: x is negative
- errno is set to EDOM. An invalid floating-point exception (FE_INVALID) is raised.
- Pole error: x is 0.0
- errno is set to ERANGE (but see BUGS). No FE_DIVBYZERO exception is returned by fetestexcept(3) for this case.
- Range error: result underflow
- errno is set to ERANGE. No FE_UNDERFLOW exception is returned by fetestexcept(3) for this case.
- Range error: result overflow
- errno is not set for this case. An overflow floating-point exception (FE_OVERFLOW) is raised.
CONFORMING TOThe functions returning double conform to SVr4, 4.3BSD, POSIX.1-2001. The others are non-standard functions that also exist on the BSDs.
BUGSOn a pole error, these functions set errno to EDOM, instead of ERANGE as POSIX.1-2004 requires.
COLOPHONThis page is part of release 3.21 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.