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man pages section 3: Extended Library Functions, Volume 2

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Updated: Thursday, June 13, 2019
 
 

modff(3M)

Name

modf, modff, modfl - decompose floating-point number

Synopsis

c99 [ flag... ] file... –lm [ library... ]
#include <math.h>

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

Description

These functions 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 themodfl() function in the object pointed to by iptr.

Return Values

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

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

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

Errors

No errors are defined.

Usage

These functions compute the function result and *iptr such that:

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

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Interface Stability
Committed
Availability
system/library/math
MT-Level
MT-Safe
Standard

See Also

ldexp(3M), frexp(3M), isnan(3M), standards(7), attributes(7)