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POEXC_BAD_ACCESS when simply casting a pointer in Obj-C
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  1. POEXC_BAD_ACCESS when simply casting a pointer in Obj-C
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    copied!<p>Frequent visitor but first post here on StackOverflow, I'm hoping that you guys might be able to help me out with this. I'm fairly new to Obj-C and XCode, and I'm faced with this really... weird... problem. Googling hasn't turned up anything whatsoever. Basically, I get an EXC_BAD_ACCESS signal on a line that doesn't do any dereferencing or anything like that that I can see. Wondering if you guys have any idea where to look for this. I've found a work around, but no idea <em>why</em> this works... The line the broken version barfs out on is the line:</p> <pre><code>LevelEntity *le = entity; </code></pre> <p>where I get my bad access signal.</p> <p>Here goes:</p> <p><strong><em>THIS VERSION WORKS</em></strong></p> <pre><code> NSArray *contacts = [self.body getContacts]; for (PhysicsContact *contact in contacts) { PhysicsBody *otherBody; if (contact.bodyA == self.body) { otherBody = contact.bodyB; } if (contact.bodyB == self.body) { otherBody = contact.bodyA; } id entity = [otherBody userData]; if (entity != nil) { LevelEntity *le = entity; CGPoint point = [contact contactPointOnBody:otherBody]; } } </code></pre> <p><strong><em>THIS VERSION DOESNT WORK</em></strong></p> <pre><code> NSArray *contacts = [self.body getContacts]; for (NSUInteger i = 0; i &lt; [contacts count]; i++) { PhysicsContact *contact = [contacts objectAtIndex:i]; PhysicsBody *otherBody; if (contact.bodyA == self.body) { otherBody = contact.bodyB; } if (contact.bodyB == self.body) { otherBody = contact.bodyA; } id entity = [otherBody userData]; if (entity != nil) { LevelEntity *le = entity; CGPoint point = [contact contactPointOnBody:otherBody]; } } </code></pre> <p>Here, the <em>only</em> difference between the two examples is the way I enumerate through my array. In the first version (which works) I use for (... in ...), where as in the second I use for (...; ...; ...). As far as I can see, these should be the same.</p> <p>This is seriously weirding me out. Anyone have any similar experience or idea whats going on here? Would be really great :)</p> <p>Cheers, Alex</p>
 

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