Manual Pages for UNIX Operating System command usage for man ilogb

Mathematical Library Functions                          ilogb(3M)



NAME
     ilogb, ilogbf, ilogbl - return an unbiased exponent

SYNOPSIS
     c99 [ flag... ] file... -lm [ library... ]
     #include 

     int ilogb(double x);


     int ilogbf(float x);


     int ilogbl(long double x);


     cc [ flag... ] file... -lm [ library... ]
     #include 

     int ilogb(double x);


     int ilogbf(float x);


     int ilogbl(long double x);


DESCRIPTION
     These functions return the exponent part of  their  argument
     x.   Formally,  the  return  value  is  the integral part of
     log(r)| x | as a signed  integral  value,  for  non-zero  x,
     where  r is the radix of the machine's floating point arith-
     metic, which is the value of FLT_RADIX defined in .

RETURN VALUES
     Upon  successful  completion,  these  functions  return  the
     exponent  part  of  x  as  a  signed integer value. They are
     equivalent to calling the  corresponding  logb(3M)  function
     and casting the returned value to type int.


     If x is 0, the  value  FP_ILOGB0  is  returned.  For  SUSv3-
     conforming  applications  compiled  with  the  c99  compiler
     driver (see standards(5)), a domain error occurs.


     If x is +_Inf, the value  INT_MAX  is  returned.  For  SUSv3-
     conforming  applications  compiled  with  the  c99  compiler
     driver, a domain error occurs.





SunOS 5.11          Last change: 12 Jul 2006                    1






Mathematical Library Functions                          ilogb(3M)



     If x is NaN, the value FP_ILOGBNAN is returned.  For  SUSv3-
     conforming  applications  compiled  with  the  c99  compiler
     driver, a domain error occurs.

ERRORS
     These functions will fail if:

     Domain Error    The x argument is zero, NaN, or +_Inf.

                     If the integer expression  (math_errhandling
                     &  MATH_ERREXCEPT)  is  non-zero,  then  the
                     invalid floating-point exception is raised.


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     feclearexcept(3M),    fetestexcept(3M),     limits.h(3HEAD),
     logb(3M),  math.h(3HEAD),  scalb(3M),  attributes(5),  stan-
     dards(5)




















SunOS 5.11          Last change: 12 Jul 2006                    2