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POCyclic Reference - protocols and subclasses
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  1. POCyclic Reference - protocols and subclasses
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    copied!<p>I'm getting some cyclic reference (I think) problems between a few classes that require imported headers due to either subclassing or protocol definitions. I can explain why things are set up this way but I'm not sure it's essential. Basically these classes are managing reciprocal to-many data relationships.</p> <p>The layout is this:<br> Class A imports Class B because it's a delegate of Class B and needs its protocol definition.<br> Class B imports Class C because it's a subclass of Class C.<br> Class C imports Class A because it's a delegate of Class A and needs its protocol definition. </p> <p>Here's some sample code that illustrates the problem. The errors I'm getting are as follows: In Class A - "Can't find protocol definition for Class_B_Delegate". In Class B - "Can't find interface declaration for Class C - superclass of Class B." In Class C - "Can't find protocol definition for Class_A_Delegate".</p> <p>Class A header:</p> <pre><code>#import &lt;Foundation/Foundation.h&gt; #import "Class_B.h" @protocol Class_A_Delegate @end @interface Class_A : NSObject &lt;Class_B_Delegate&gt; { } @end </code></pre> <p>Class B header:</p> <pre><code>#import &lt;Foundation/Foundation.h&gt; #import "Class_C.h" @protocol Class_B_Delegate &lt;NSObject&gt; @end @interface Class_B : Class_C { } @end </code></pre> <p>Class C Header:</p> <pre><code>#import &lt;Foundation/Foundation.h&gt; #import "Class_A.h" @interface Class_C : NSObject &lt;Class_A_Delegate&gt; { } @end </code></pre>
 

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