MODF(P) POSIX Programmer's Manual MODF(P)
modf, modff, modfl - decompose a floating-point number
double modf(double x, double *iptr);
float modff(float value, float *iptr);
long double modfl(long double value, long double *iptr);
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.
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.
No errors are defined.
The following sections are informative.
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.
frexp() , isnan() , ldexp() , the Base Definitions volume of IEEE Std 1003.1-2001,
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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 MODF(P)