Section: Linux Programmer's Manual (3) Updated: 2010-09-12 Local index
log2, log2f, log2l - base-2 logarithmic function
double log2(double x);
float log2f(float x);
long double log2l(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
function returns the base 2 logarithm of x.
On success, these functions return the base 2 logarithm of
For special cases, including where
is 0, 1, negative, infinity, or NaN, see
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
These functions first appeared in glibc in version 2.1.
The variant returning
also conforms to
This page is part of release 3.27 of the Linux
A description of the project,
and information about reporting bugs,
can be found at
- RETURN VALUE
- CONFORMING TO
- SEE ALSO
This document was created by
using the manual pages.
Time: 21:49:36 GMT, April 16, 2011