формат точки (point format)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
round, roundf, roundl — round to the nearest integer value in a
floating-point format
Синопсис (Synopsis)
#include <math.h>
double round(double x);
float roundf(float x);
long double roundl(long double x);
Описание (Description)
The functionality described on this reference page is aligned
with the ISO C standard. Any conflict between the requirements
described here and the ISO C standard is unintentional. This
volume of POSIX.1‐2017 defers to the ISO C standard.
These functions shall round their argument to the nearest integer
value in floating-point format, rounding halfway cases away from
zero, regardless of the current rounding direction.
Возвращаемое значение (Return value)
Upon successful completion, these functions shall return the
rounded integer value. The result shall have the same sign as x.
If x is NaN, a NaN shall be returned.
If x is ±0 or ±Inf, x shall be returned.
Ошибки (Error)
No errors are defined.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
The integral value returned by these functions need not be
expressible as an intmax_t. The return value should be tested
before assigning it to an integer type to avoid the undefined
results of an integer overflow.
These functions may raise the inexact floating-point exception if
the result differs in value from the argument.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
feclearexcept(3p), fetestexcept(3p)
The Base Definitions volume of POSIX.1‐2017, Section 4.20,
Treatment of Error Conditions for Mathematical Functions,
math.h(0p)
