What does it mean that objc_msgSend() is passed "a pointer to the reciever's data"? <p>In Apple's ObjC Runtime Guide, it describes what the <code>objc_msgSend()</code> function does for dynamic dispatch:</p> <blockquote> <ol> <li>It first finds the procedure (method implementation) that the selector refers to. Since the same method can be implemented differently by separate classes, the precise procedure that it finds depends on the class of the receiver.</li> <li>It then calls the procedure, passing it the <strong>receiving object (a pointer to its data)</strong>, along with any arguments that were specified for the method.</li> <li>Finally, it passes on the return value of the procedure as its own return value.</li> </ol> </blockquote> <p>I was confused in the second step, where it mentioned <strong>"receiving object (a pointer to its data)</strong></p> <p>What is that?</p> <p>Can somebody give me a illustration to clarify it?</p>