(a) If the bylaws of a corporation require notice of a meeting to be given to a director, a written waiver of the notice signed by the director entitled to the notice, before or after the meeting, is equivalent to the giving of the notice.
(b) The attendance of a director at a board meeting constitutes a waiver of notice of the meeting, unless the director attends the meeting for the express purpose of objecting to the transaction of business at the meeting because the meeting has not been lawfully called or convened.
(c) A waiver of notice of a board meeting is not required to specify the business to be transacted at the meeting or the purpose of the meeting, unless required by the bylaws.