NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO |
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log2(3) Library Functions Manual log2(3)
log2, log2f, log2l - base-2 logarithmic function
Math library (libm, -lm)
#include <math.h> double log2(double x); float log2f(float x); long double log2l(long double x); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): log2(), log2f(), log2l(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
These functions return the base 2 logarithm of x.
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).
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).
For an explanation of the terms used in this section, see attributes(7). ┌──────────────────────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├──────────────────────────────────────┼───────────────┼─────────┤ │log2(), log2f(), log2l() │ Thread safety │ MT-Safe │ └──────────────────────────────────────┴───────────────┴─────────┘
C11, POSIX.1-2008.
glibc 2.1. C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD.
cbrt(3), clog2(3), log(3), log10(3), sqrt(3)
Linux man-pages 6.04 2023-03-30 log2(3)
Pages that refer to this page: log10(3), log(3)