NAME

       powerof2 - test if a value is a power of 2

LIBRARY

       Standard C library (libc)

SYNOPSIS

       #include <sys/param.h>

       int powerof2(x);

DESCRIPTION

       This macro returns true if x is a power of 2, and false otherwise.

       0  is  considered  a  power of 2.  This can make sense considering wrapping of unsigned integers, and has
       interesting properties.

RETURN VALUE

       True or false, if x is a power of 2 or not, respectively.

STANDARDS

       BSD.

CAVEATS

       The arguments may be evaluated more than once.

       Because this macro is implemented using bitwise operations, some negative  values  can  invoke  undefined
       behavior.   For example, the following invokes undefined behavior: powerof2(INT_MIN);.  Call it only with
       unsigned types to be safe.

SEE ALSO

       stdc_bit_ceil(3), stdc_bit_floor(3)