Returns the exponent part of its argument.

    This function is supported on OpenVMS Integrity servers and
    Alpha only.

    Format

      #include  <math.h>

      int ilogb  (double x);

      int ilogbf  (float x);

      int ilogbl  (long double x);

1 - Argument

 x

    A real value.

2 - Description

    The ilogb functions return the exponent part of their argument
    x. Formally, the return value is the integral part of logr|x| as
    a signed integral value, for nonzero x, where r is the radix of
    the machine's floating-point arithmetic, which is the value of
    FLT_RADIX defined in <float.h>.

3 - Return Values

    n                  Upon success, the exponent part of x as a
                       signed integer value. These functions are
                       equivalent to calling the corresponding logb
                       function and casting the returned value to
                       type int.