извлечь мантиссу и экспоненту из числа с двойной точностью (extract mantissa and exponent from a double precision number)
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)
frexp, frexpf, frexpl — extract mantissa and exponent from a
double precision number
Синопсис (Synopsis)
#include <math.h>
double frexp(double num, int *exp);
float frexpf(float num, int *exp);
long double frexpl(long double num, int *exp);
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 break a floating-point number num into a
normalized fraction and an integral power of 2. The integer
exponent shall be stored in the int object pointed to by exp.
Возвращаемое значение (Return value)
For finite arguments, these functions shall return the value x,
such that x has a magnitude in the interval [½,1) or 0, and num
equals x times 2 raised to the power *exp.
If num is NaN, a NaN shall be returned, and the value of *exp is
unspecified.
If num is ±0, ±0 shall be returned, and the value of *exp shall
be 0.
If num is ±Inf, num shall be returned, and the value of *exp is
unspecified.
Ошибки (Error)
No errors are defined.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
isnan(3p), ldexp(3p), modf(3p)
The Base Definitions volume of POSIX.1‐2017, math.h(0p)
