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nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl - floating-point number manipulation

#include<math.h>doublenextafter(doublex,doubley);floatnextafterf(floatx,floaty);longdoublenextafterl(longdoublex,longdoubley);doublenexttoward(doublex,longdoubley);floatnexttowardf(floatx,longdoubley);longdoublenexttowardl(longdoublex,longdoubley);Link with-lm. Feature Test Macro Requirements for glibc (seefeature_test_macros(7)):nextafter(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _ISOC99_SOURCE; orcc-std=c99nextafterf(),nextafterl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; orcc-std=c99nexttoward(),nexttowardf(),nexttowardl(): _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE;cc-std=c99

Thenextafter() functions return the next representable floating-point value followingxin the direction ofy. Ifyis less thanx, these functions will return the largest representable number less thanx. Ifxequalsy, the functions returny. Thenexttoward() functions do the same as thenextafter() functions, except that they have alongdoublesecond argument.

On success, these functions return the next representable floating- point value afterxin the direction ofy. Ifxequalsy, theny(cast to the same type asx) is returned. Ifxoryis a NaN, a NaN is returned. Ifxis finite, and the result would overflow, a range error occurs, and the functions returnHUGE_VAL,HUGE_VALF, orHUGE_VALL, respectively, with the correct mathematical sign. Ifxis not equal toy, and the correct function result would be subnormal, zero, or underflow, a range error occurs, and either the correct value (if it can be represented), or 0.0, is returned.

Seemath_error(7) for information on how to determine whether an error has occurred when calling these functions. The following errors can occur: Range error: result overflow An overflow floating-point exception (FE_OVERFLOW) is raised. Range error: result is subnormal or underflows An underflow floating-point exception (FE_UNDERFLOW) is raised. These functions do not seterrno.

C99, POSIX.1-2001. This function is defined in IEC 559 (and the appendix with recommended functions in IEEE 754/IEEE 854).

In glibc version 2.5 and earlier, these functions do not raise an underflow floating-point (FE_UNDERFLOW) exception when an underflow occurs.

nearbyint(3)

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