Description

   logb() returns a signed integer converted to double-precision
   floating-point and so chosen that 1 <= |x|/2**n < 2 unless x = 0
   or |x| = infinity.

   IEEE Std 754 defines logb(+infinity) = +infinity and logb(0) =
   -infinity. The latter is required to signal division by zero.


                          Entry-Point Names

   Generic
   Function   Data Type   OpenVMS        Tru64 UNIX
   Name       Required

   logb       S_FLOAT     math$logb_s    logbf
              T_FLOAT     math$logb_t    logb
              X_FLOAT     math$logb_x    logbl
              F_FLOAT     math$logb_f
              G_FLOAT     math$logb_g