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Y0(3P) POSIX Programmer's Manual Y0(3P)PROLOGThis manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may dif- fer (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.NAMEy0, y1, yn - Bessel functions of the second kindSYNOPSIS#include<math.h>doubley0(doublex);doubley1(doublex);doubleyn(intn,doublex);DESCRIPTIONThey0(),y1(), andyn() functions shall compute Bessel functions ofxof the second kind of orders 0, 1, andn, respectively. An application wishing to check for error situations should seterrnoto zero and callfeclearex-cept(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.RETURNVALUEUpon successful completion, these functions shall return the relevant Bessel value ofxof the second kind. Ifxis NaN, NaN shall be returned. If thexargument to these functions is negative, -HUGE_VAL or NaN shall be returned, and a domain error may occur. Ifxis 0.0, -HUGE_VAL shall be returned and a range 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.ERRORSThese functions may fail if: Domain Error The value ofxis negative. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, thenerrnoshall be set to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point excep- tion shall be raised. Range Error The value ofxis 0.0, or the correct result would cause overflow. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, thenerrnoshall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point excep- tion shall be raised. Range Error The value ofxis too large in magnitude, or the correct result would cause underflow. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, thenerrnoshall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow floating-point exception shall be raised.Thefollowingsectionsareinformative.EXAMPLESNone.APPLICATIONUSAGEOn error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are indepen- dent of each other, but at least one of them must be non-zero.RATIONALENone.FUTUREDIRECTIONSNone.SEEALSOfeclearexcept(),fetestexcept(),isnan(),j0(), the Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18, Treatment of Error Conditions for Mathematical Functions,<math.h>COPYRIGHTPortions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Stan- dard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica- tions 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 Stan- dard, 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 2003 Y0(3P)