манипуляции с числами с плавающей запятой (floating-point number manipulation)
Имя (Name)
nextafter, nextafterf, nextafterl, nexttoward, nexttowardf,
nexttowardl - floating-point number manipulation
Синопсис (Synopsis)
#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():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| _XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
nextafterf(), nextafterl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
nexttoward(), nexttowardf(), nexttowardl():
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE
|| _POSIX_C_SOURCE >= 200112L
Описание (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.
Возвращаемое значение (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.
Ошибки (Error)
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
errno is set to ERANGE. An overflow floating-point
exception (FE_OVERFLOW) is raised.
Range error: result is subnormal or underflows
errno is set to ERANGE. An underflow floating-point
exception (FE_UNDERFLOW) is raised.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│nextafter(), nextafterf(), │ Thread safety │ MT-Safe │
│nextafterl(), nexttoward(), │ │ │
│nexttowardf(), nexttowardl() │ │ │
└──────────────────────────────────────┴───────────────┴─────────┘
Стандарты (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).
Ошибки (баги) (Bugs)
In glibc version 2.5 and earlier, these functions do not raise an
underflow floating-point (FE_UNDERFLOW) exception when an
underflow occurs.
Before glibc version 2.23 these functions did not set errno.
Смотри также (See also)
nearbyint(3)
