Интерактивная система просмотра системных руководств (man-ов) log2f (3) log2f ( Русские man: Библиотечные вызовы ) >> log2f ( Linux man: Библиотечные вызовы ) log2f ( POSIX man: Библиотечные вызовы )
NAME
log2, log2f, log2l - base-2 logarithmic function
SYNOPSIS
#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
log2 (),
log2f (),
log2l ():
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or
cc -std=c99
DESCRIPTION
The
log2 ()
function returns the base 2 logarithm of x .
RETURN VALUE
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
ERRORS
See
math_error
For a discussion of the errors that can occur for these functions, see
log
VERSIONS
These functions first appeared in glibc in version 2.1.
CONFORMING TO
C99, POSIX.1-2001.
The variant returning
double
also conforms to
SVr4, 4.3BSD, C89.
SEE ALSO
cbrt clog2 sqrt
COLOPHON
This page is part of release 3.14 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
Index
NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
VERSIONS
CONFORMING TO
SEE ALSO
COLOPHON
