`modf.3p` ( 3 )

номер точки (point 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)

modf, modff, modfl — decompose a floating-point number

Синопсис (Synopsis)

#include <math.h>

double modf(double x, double *iptr); float modff(float value, float *iptr); long double modfl(long double value, long double *iptr);

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 the argument x into integral and fractional parts, each of which has the same sign as the argument. It stores the integral part as a double (for the modf() function), a float (for the modff() function), or a long double (for the modfl() function), in the object pointed to by iptr.

Возвращаемое значение (Return value)

Upon successful completion, these functions shall return the signed fractional part of x.

If x is NaN, a NaN shall be returned, and *iptr shall be set to a NaN.

If x is ±Inf, ±0 shall be returned, and *iptr shall be set to ±Inf.

Ошибки (Error)

No errors are defined.

The following sections are informative.

Примеры (Examples)

None.

Использование в приложениях (Application usage)

The modf() function computes the function result and *iptr such that:

a = modf(x, iptr) ; x == a+*iptr ;

allowing for the usual floating-point inaccuracies.

Обоснование (Rationale)

None.

Будущие направления (Future directions)