log2l(3)

1LOG2(3)                    Linux Programmer's Manual                   LOG2(3)
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NAME

6       log2, log2f, log2l - base-2 logarithmic function
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SYNOPSIS

9       #include <math.h>
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11       double log2(double x);
12       float log2f(float x);
13       long double log2l(long double x);
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15       Link with -lm.
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17   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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19       log2(), log2f(), log2l(): _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or
20       cc -std=c99
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DESCRIPTION

23       The log2() function returns the base 2 logarithm of x.
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RETURN VALUE

26       On success, these functions return the base 2 logarithm of x.
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28       For special cases, including where x is 0, 1,  negative,  infinity,  or
29       NaN, see log(3).
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ERRORS

32       See  math_error(7) for information on how to determine whether an error
33       has occurred when calling these functions.
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35       For a discussion of the errors that can occur for these functions,  see
36       log(3).
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VERSIONS

39       These functions first appeared in glibc in version 2.1.
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CONFORMING TO

42       C99, POSIX.1-2001.  The variant returning double also conforms to SVr4,
43       4.3BSD, C89.
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COLOPHON

49       This page is part of release 3.22 of the Linux  man-pages  project.   A
50       description  of  the project, and information about reporting bugs, can
51       be found at http://www.kernel.org/doc/man-pages/.
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55                                  2008-08-11                           LOG2(3)