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Y0(3) Linux Programmer's Manual Y0(3)NAMEy0, y0f, y0l, y1, y1f, y1l, yn, ynf, ynl - Bessel functions of the second kindSYNOPSIS#include<math.h>doubley0(doublex);doubley1(doublex);doubleyn(intn,doublex);floaty0f(floatx);floaty1f(floatx);floatynf(intn,floatx);longdoubley0l(longdoublex);longdoubley1l(longdoublex);longdoubleynl(intn,longdoublex);Link with-lm. Feature Test Macro Requirements for glibc (see feature_test_macros(7)):y0(),y1(),yn(): _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCEy0f(),y0l(),y1f(),y1l(),ynf(),ynl(): _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 600DESCRIPTIONThey0() andy1() functions return Bessel functions ofxof the second kind of orders 0 and 1, respectively. Theyn() function returns the Bessel function ofxof the second kind of ordern. The value ofxmust be positive. They0f() etc. andy0l() etc. functions are versions that take and returnfloatandlongdoublevalues, respec- tively.RETURNVALUEOn success, these functions return the appropriate Bessel value of the second kind forx. Ifxis a NaN, a NaN is returned. Ifxis negative, a domain error occurs, and the functions return -HUGE_VAL, -HUGE_VALF, or -HUGE_VALL, respec- tively. (POSIX.1-2001 also allows a NaN return for this case.) Ifxis 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 If the result overflows, a range error occurs, and the functions return -HUGE_VAL, -HUGE_VALF, or -HUGE_VALL, respectively. (POSIX.1-2001 also allows a 0.0 return for this case.)ERRORSSee math_error(7) for information on how to determine whether an error has occurred when calling these func- tions. The following errors can occur: Domain error:xis negativeerrnois set toEDOM. An invalid floating-point exception (FE_INVALID) is raised. Pole error:xis 0.0errnois set toERANGE(but see BUGS). NoFE_DIVBYZEROexception is returned by fetestexcept(3) for this case. Range error: result underflowerrnois set toERANGE. NoFE_UNDERFLOWexception is returned by fetestexcept(3) for this case. Range error: result overflowerrnois not set for this case. An overflow floating-point exception (FE_OVERFLOW) is raised.CONFORMINGTOThe functions returningdoubleconform 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 seterrnotoEDOM, instead ofERANGEas POSIX.1-2004 requires. In glibc version 2.3.2 and earlier, these functions do not raise an invalid floating-point exception (FE_INVALID) when a domain error occurs.SEEALSOj0(3)COLOPHONThis page is part of release 3.22 of the Linuxman-pagesproject. A description of the project, and informa- tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. 2008-08-10 Y0(3)