MODF(P) POSIX Programmer's Manual MODF(P)NAME
modf, modff, modfl - decompose a floating-point number
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);
DESCRIPTION
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.
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.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
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.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSOfrexp() , isnan() , ldexp() , the Base Definitions volume of
IEEE Std 1003.1-2001, <math.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 MODF(P)
