NAME    [Toc]    [Back]

       ilogb - Returns an unbiased exponent

SYNOPSIS    [Toc]    [Back]

       #include <math.h>

       int ilogb(
               double x ); int ilogbf(
               float x ); int ilogbl(
               long double x );

LIBRARY    [Toc]    [Back]

       Math Library (libm)

STANDARDS    [Toc]    [Back]

       Interfaces  documented  on  this reference page conform to
       industry standards as follows:

       ilogb():  XPG4-UNIX

       Refer to the standards(5) reference page for more information
 about industry standards and associated tags.

DESCRIPTION    [Toc]    [Back]

       The  ilogb(),  ilogbf(), and ilogbl() functions return the
       integral part of the base r logarithm of (|x|) as a signed
       integral value for non-zero x, where r is the radix of the
       machine's floating point arithmetic.

       The  following  table  describes  function   behavior   in
       response to exceptional arguments:

       -----------------------------------------------------------------------
       Function                       Exceptional Argument   Routine Behavior
       -----------------------------------------------------------------------
       ilogb(), ilogbf(), ilogbl()    |x| = infinity         INT_MAX
       ilogb(), ilogbf(), ilogbl()    x = 0, NaN             INT_MIN
       -----------------------------------------------------------------------




                                                         ilogb(3)