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NEXTAFTER(3) | Linux Programmer's Manual | NEXTAFTER(3) |
NAME¶
nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl - floating-point number manipulationSYNOPSIS¶
#include <math.h> double nextafter(double x, double y);Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
nextafter():
_ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L
|| _XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
|| _XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
_ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE
|| _POSIX_C_SOURCE >= 200112L
DESCRIPTION¶
The nextafter(), nextafterf(), and nextafterl() 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(), nexttowardf(), and nexttowardl() functions do the same as the corresponding nextafter() functions, except that they have a long double second argument.RETURN VALUE¶
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.ERRORS¶
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.
ATTRIBUTES¶
For an explanation of the terms used in this section, see attributes(7).Interface | Attribute | Value |
nextafter (), nextafterf (), nextafterl (), nexttoward (), nexttowardf (), nexttowardl () | Thread safety | MT-Safe |
CONFORMING TO¶
C99, POSIX.1-2001, POSIX.1-2008. This function is defined in IEC 559 (and the appendix with recommended functions in IEEE 754/IEEE 854).BUGS¶
In glibc version 2.5 and earlier, these functions do not raise an underflow floating-point (FE_UNDERFLOW) exception when an underflow occurs.SEE ALSO¶
nearbyint(3)COLOPHON¶
This page is part of release 4.10 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.2016-03-15 | GNU |