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j0, j1, jn - Bessel functions of the first kind

#include <math.h>

double j0(doublex);

double j1(doublex);

double jn(intn, doublex);

The

j0(),j1(), andjn() functions shall compute Bessel functions ofxof the first kind of orders 0, 1, andn, respectively.An application wishing to check for error situations should set

errnoto zero and callfeclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, iferrnois non-zero orfetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.

Upon successful completion, these functions shall return the relevant Bessel value of

xof the first kind.If the

xargument is too large in magnitude, or the correct result would cause underflow, 0 shall be returned and a range error may occur.If

xis NaN, a NaN shall be returned.

These functions may fail if:

If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then

Range Error The value of xwas too large in magnitude, or an underflow occurred.errnoshall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow floating-point exception shall be raised.

No other errors shall occur.

The following sections are informative.

None.

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.

None.

None.

feclearexcept() ,fetestexcept() ,isnan() ,y0() , the Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18, Treatment of Error Conditions for Mathematical Functions,<math.h>

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group |
J0 (P) | 2003 |