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NEXTAFTER(3) Linux Programmer's Manual NEXTAFTER(3)
nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl -
floating-point number manipulation
#include <math.h>
double nextafter(double x, double y);
float nextafterf(float x, float y);
long double nextafterl(long double x, long double y);
double nexttoward(double x, long double y);
float nexttowardf(float x, long double y);
long double nexttowardl(long double x, long double y);
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;
or cc -std=c99
nextafterf(), nextafterl():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
nexttoward(), nexttowardf(), nexttowardl():
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or cc -std=c99
The nextafter() functions return the next representable floating-point value
following x in the direction of y. If y is less than x, these functions will
return the largest representable number less than x.
If x equals y, the functions return y.
The nexttoward() functions do the same as the nextafter() functions, except
that they have a long double second argument.
On success, these functions return the next representable floating-point value
after x in the direction of y.
If x equals y, then y (cast to the same type as x) is returned.
If x or y is a NaN, a NaN is returned.
If x is finite, and the result would overflow, a range error occurs, and the
functions return HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively, with the
correct mathematical sign.
If x is not equal to y, 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.
See math_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 set 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)
This page is part of release 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
GNU 2010-09-20 NEXTAFTER(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface