Decomposes a floating-point number.

    Format

      #include  <math.h>

      double modf  (double x, double *iptr);

      float modff  (float x, float *iptr);
                   (Integrity servers, Alpha)

      long double modfl  (long double x, long double *iptr);
                         (Integrity servers, Alpha)

1 - Arguments

 x

    An object of type double, float, or long double.

 iptr

    A pointer to an object of type double, float, or long double to
    match the type of x.

2 - Description

    The modf functions decompose their first argument x into a
    positive fractional part f and an integer part i, each of which
    has the same sign as x.

    The functions return f and assign i to the object pointed to by
    the second argument (iptr).

3 - Return Values

    x                  The fractional part of the argument x.
    NaN                x is NaN; errno is set to EDOM and *iptr is
                       set to NaN.
    0                  Underflow occurred; errno is set to ERANGE.