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 ALSO

       frexp() , 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 .