log2f(3) - f38

1log2(3)                    Library Functions Manual                    log2(3)
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NAME

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

9       Math library (libm, -lm)
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SYNOPSIS

12       #include <math.h>
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14       double log2(double x);
15       float log2f(float x);
16       long double log2l(long double x);
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18   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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20       log2(), log2f(), log2l():
21           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
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DESCRIPTION

24       These functions return the base 2 logarithm of x.
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RETURN VALUE

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

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

40       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
41       tributes(7).
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43       ┌────────────────────────────────────────────┬───────────────┬─────────┐
44       │Interface                                   │ Attribute     │ Value   │
45       ├────────────────────────────────────────────┼───────────────┼─────────┤
46       │log2(), log2f(), log2l()                    │ Thread safety │ MT-Safe │
47       └────────────────────────────────────────────┴───────────────┴─────────┘
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STANDARDS

50       C11, POSIX.1-2008.
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HISTORY

53       glibc 2.1.  C99, POSIX.1-2001.
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55       The variant returning double also conforms to SVr4, 4.3BSD.
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