test if two integers share a `1' bit
Major Section:  PROGRAMMING

When integers x and y are viewed in their two's complement representation, (logtest x y) is true if and only if there is some position for which both x and y have a `1' bit in that position.

The guard for logtest requires its arguments to be integers. Logtest is defined in Common Lisp. See any Common Lisp documentation for more information.