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   nexttowardl    ( 3 )

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)