Manpages - log2.3

log2, log2f, log2l - base-2 logarithmic function

  #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

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).

These functions first appeared in glibc in version 2.1.

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

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

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

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

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