1J0(3P) POSIX Programmer's Manual J0(3P)
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6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
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12 j0, j1, jn - Bessel functions of the first kind
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15 #include <math.h>
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17 double j0(double x);
18 double j1(double x);
19 double jn(int n, double x);
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23 The j0(), j1(), and jn() functions shall compute Bessel functions of x
24 of the first kind of orders 0, 1, and n, respectively.
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26 An application wishing to check for error situations should set errno
27 to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these
28 functions. On return, if errno is non-zero or fetestexcept(FE_INVALID
29 | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has
30 occurred.
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33 Upon successful completion, these functions shall return the relevant
34 Bessel value of x of the first kind.
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36 If the x argument is too large in magnitude, or the correct result
37 would cause underflow, 0 shall be returned and a range error may occur.
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39 If x is NaN, a NaN shall be returned.
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42 These functions may fail if:
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44 Range Error
45 The value of x was too large in magnitude, or an underflow
46 occurred.
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48 If the integer expression (math_errhandling & MATH_ERRNO) is non-zero,
49 then errno shall be set to [ERANGE]. If the integer expression
50 (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow
51 floating-point exception shall be raised.
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54 No other errors shall occur.
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56 The following sections are informative.
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59 None.
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62 On error, the expressions (math_errhandling & MATH_ERRNO) and
63 (math_errhandling & MATH_ERREXCEPT) are independent of each other, but
64 at least one of them must be non-zero.
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67 None.
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70 None.
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73 feclearexcept(), fetestexcept(), isnan(), y0(), the Base Definitions
74 volume of IEEE Std 1003.1-2001, Section 4.18, Treatment of Error Condiā
75 tions for Mathematical Functions, <math.h>
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78 Portions of this text are reprinted and reproduced in electronic form
79 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
80 -- Portable Operating System Interface (POSIX), The Open Group Base
81 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
82 Electrical and Electronics Engineers, Inc and The Open Group. In the
83 event of any discrepancy between this version and the original IEEE and
84 The Open Group Standard, the original IEEE and The Open Group Standard
85 is the referee document. The original Standard can be obtained online
86 at http://www.opengroup.org/unix/online.html .
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90IEEE/The Open Group 2003 J0(3P)