log2(3) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO

log2(3)                 Library Functions Manual                 log2(3)

NAME         top

       log2, log2f, log2l - base-2 logarithmic function

LIBRARY         top

       Math library (libm, -lm)

SYNOPSIS         top

       #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

DESCRIPTION         top

       These functions return the base 2 logarithm of x.

RETURN VALUE         top

       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         top

       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).

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌─────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                           Attribute     Value   │
       ├─────────────────────────────────────┼───────────────┼─────────┤
       │ log2(), log2f(), log2l()            │ Thread safety │ MT-Safe │
       └─────────────────────────────────────┴───────────────┴─────────┘

STANDARDS         top

       C11, POSIX.1-2008.

HISTORY         top

       glibc 2.1.  C99, POSIX.1-2001.

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

SEE ALSO         top

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

Linux man-pages (unreleased)     (date)                          log2(3)

Pages that refer to this page: log10(3)log(3)