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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
       The functionality described on this reference page is aligned with  the
       ISO C  standard.  Any  conflict between the requirements described here
       and the ISO C standard is unintentional. This  volume  of  POSIX.1-2008
       defers to the ISO C standard.
       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 POSIX.1-2008, <math.h>
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) 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.unix.org/online.html .
       Any  typographical  or  formatting  errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files  to  man page format. To report such errors, see https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                             MODF(3P)