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MODF(3P)                   POSIX Programmer's Manual                  MODF(3P)

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.
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 .

IEEE/The Open Group                  2003                             MODF(3P)