How to find out if a global variable has changed in c++?
<p>I have a silly question! Let's suppose you have a <em>global variable</em> that is used all over the project and you are going to do something when it changes ,for example calling a function .<br>
 One simple way is to <em>call your function after every change</em>. But what if this global variable is part of a library and will be used outside .Is there any better solution ?</p>
