J0(3) Library Functions Manual J0(3)

j0 j1 jn — Bessel functions of the first kind

#include <math.h>

double j0(double x);
double j1(double x);
double jn(int n, double x);

The j0() , j1() and jn() functions compute Bessel functions of x of the first kind of orders 0, 1 and n respectively.

An application wishing to check for error situations should set errno to 0 before calling , or . If errno is non-zero on return, or the return value is NaN, an error has occurred.

Upon successful completion, j0() , j1() and jn() return the relevant Bessel value of x of the first kind.

If the x argument is too large in magnitude, 0 is returned and errno may be set to [ERANGE].

If x is NaN, NaN is returned and errno may be set to [EDOM].

If the correct result would cause underflow, 0 is returned and errno may be set to [ERANGE].

The j0() , j1() and jn() functions may fail if:

The value of x is NaN.
The value of x was too large in magnitude, or underflow occurred.

No other errors will occur.

None.

None.

None.

isnan(3) , y0(3) , <math.h> .

Derived from Issue 1 of the SVID.

February 1997 posix.fail