LOG2(3)                   (2017-09-15)                    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).     allbox;    lbw24    lb    lb   l   l   l.
          Interface Attribute Value  T{   log2(),   log2f(),   log2l()
          T}   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

     Page 1                       Plan 9             (printed 5/17/22)

     LOG2(3)                   (2017-09-15)                    LOG2(3)

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

     COLOPHON
          This page is part of release 5.10  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/.

     Page 2                       Plan 9             (printed 5/17/22)