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log2(3)


NAME

   log2, log2f, log2l - base-2 logarithmic function

SYNOPSIS

   #include <math.h>

   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():
       _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

DESCRIPTION

   These functions return the base 2 logarithm of x.

RETURN VALUE

   On success, these functions return the base 2 logarithm of x.

   For  special  cases,  including where x is 0, 1, negative, infinity, or
   NaN, see log(3).

ERRORS

   See math_error(7) for information on how to determine whether an  error
   has occurred when calling these functions.

   For  a discussion of the errors that can occur for these functions, see
   log(3).

VERSIONS

   These functions first appeared in glibc in version 2.1.

ATTRIBUTES

   For  an  explanation  of  the  terms  used   in   this   section,   see
   attributes(7).

   
   Interface                 Attribute      Value   
   
   log2(), log2f(), log2l()  Thread safety  MT-Safe

CONFORMING TO

   C99, POSIX.1-2001, POSIX.1-2008.

   The variant returning double also conforms to SVr4, 4.3BSD.

SEE ALSO

   cbrt(3), clog2(3), log(3), log10(3), sqrt(3)

COLOPHON

   This  page  is  part of release 4.09 of the Linux man-pages project.  A
   description of the project, information about reporting bugs,  and  the
   latest     version     of     this    page,    can    be    found    at
   https://www.kernel.org/doc/man-pages/.

                              2016-03-15                           LOG2(3)



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