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    <p>How does the Observer pattern work ?</p> <ul> <li>Observable objects are "watched" by Observer objects</li> <li>When an Observable is modified, it notifies all of its observers a change has been made, for example by calling their "update" or "notify" function (or whatever)</li> </ul> <p>So, in terms of <strong>signals</strong> and <strong>slots</strong>. The basics are that you connect signals to slots, which will be called each time the signal they're connected to is emitted.</p> <p>You will find that it is very easy to use in the Observer pattern : just create a signal in the Observable that will be connected to the slot of each Observer used to update it.</p> <p>in case of a change in the Observable. Instead of looping through the list of all your observers, and calling their <code>update</code> method one after another, just emit the signal. The corresponding slots will magically be called.</p> <p>To go further, you could for example have a slot in the Observable, connected to a signal that an Observer will emit to tell the Observable it has to be noticed in case of changes...</p> <p>Can't get you a fully working example code since I never used <code>Boost::signals2</code>, but you should take a look at <a href="https://stackoverflow.com/questions/10418582/how-do-i-use-boostsignals-to-implement-the-observer-pattern" title="How do I use boost::signals to implement the observer pattern?">How do I use boost::signals to implement the observer pattern?</a> and <a href="https://stackoverflow.com/questions/2225162/observer-design-pattern-in-c%20">Observer design pattern in C++</a> to get you going :)</p>
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    1. COthank you, now I understand it.
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