Message        Empty character constant.

 Description    In some modes the HP C compiler will allow a null
                character constant.  The compiler will give this
                constant a value of zero.  Accepting an empty
                character constant is a language extension.  Empty
                character constants are not valid in standard C.
                Writing programs that rely on this behavior might
                prevent the program from being compiled on other
                platforms.

 User Action    Replace the empty character constant with '\0'.