1MODF(P)                    POSIX Programmer's Manual                   MODF(P)
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NAME

6       modf, modff, modfl - decompose a floating-point number
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SYNOPSIS

9       #include <math.h>
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11       double modf(double x, double *iptr);
12       float modff(float value, float *iptr);
13       long double modfl(long double value, long double *iptr);
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DESCRIPTION

17       These functions shall break the argument x into integral and fractional
18       parts, each of which has the same sign as the argument. It  stores  the
19       integral  part  as a double (for the modf() function), a float (for the
20       modff() function), or a long double (for the modfl() function), in  the
21       object pointed to by iptr.
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RETURN VALUE

24       Upon  successful  completion,  these  functions shall return the signed
25       fractional part of x.
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27       If x is NaN, a NaN shall be returned, and *iptr shall be set to a NaN.
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29       If x is ±Inf, ±0 shall be returned, and *iptr shall be set to ±Inf.
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ERRORS

32       No errors are defined.
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34       The following sections are informative.
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EXAMPLES

37       None.
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APPLICATION USAGE

40       The modf() function computes the function result and *iptr such that:
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43              a = modf(x, iptr) ;
44              x == a+*iptr ;
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46       allowing for the usual floating-point inaccuracies.
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RATIONALE

49       None.
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FUTURE DIRECTIONS

52       None.
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SEE ALSO

55       frexp()  ,  isnan()  ,  ldexp()  ,  the  Base  Definitions  volume   of
56       IEEE Std 1003.1-2001, <math.h>
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59       Portions  of  this text are reprinted and reproduced in electronic form
60       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
61       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
62       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
63       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
64       event of any discrepancy between this version and the original IEEE and
65       The  Open Group Standard, the original IEEE and The Open Group Standard
66       is the referee document. The original Standard can be  obtained  online
67       at http://www.opengroup.org/unix/online.html .
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71IEEE/The Open Group                  2003                              MODF(P)
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