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

Synopsis

Description

Return Value

Errors

Bugs

Colophon

#include <math.h>

double nextafter(doublex, doubley);

float nextafterf(floatx, floaty);

long double nextafterl(long doublex, long doubley);

double nexttoward(doublex, long doubley);

float nexttowardf(floatx, long doubley);

long double nexttowardl(long doublex, long doubley);Link with

-lm.Feature Test Macro Requirements for glibc (see

feature_test_macros(7)):

nextafter():_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;

orcc -std=c99

nextafterf(),nextafterl():_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;

orcc -std=c99

nexttoward(),nexttowardf(),nexttowardl():_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;

orcc -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.If

xequalsy, the functions returny.The

nexttoward() functions do the same as thenextafter() functions, except that they have along doublesecond argument.

On success, these functions return the next representable floating-point value afterxin the direction ofy.If

xequalsy, theny(cast to the same type asx) is returned.If

xoryis a NaN, a NaN is returned.If

xis 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.If

xis 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:

These functions do not set

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.errno.

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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GNU |
NEXTAFTER (3) | 2010-09-20 |