LOG2(3) 		   Linux Programmers Manual		      LOG2(3)



NAME
       log2, log2f, log2l - base-2 logarithmic function

SYNOPSIS
       #include 

       double log2(double x);
       float log2f(float x);
       long double log2l(long double x);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       log2(), log2f(), log2l(): _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or
       cc -std=c99

DESCRIPTION
       The log2() function returns the base 2 logarithm of x.

ERRORS
       The log2() function can return the following error:

       EDOM   The argument x is negative.

       ERANGE The argument x is zero.  The log of zero is not  defined	(minus
	      infinity).

CONFORMING TO
       SVr4, 4.3BSD, C89.  The float and long double variants are C99 require
       ments.

SEE ALSO
       cbrt(3), clog2(3), sqrt(3)

COLOPHON
       This page is part of release 3.05 of the Linux  man-pages  project.   A
       description  of	the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



				  2007-07-26			       LOG2(3)