title: variable is not assignable (missing __block type specifier)
body: <p>I have an error in my code that i cannot fix..
  here is my code.. it is inside the first if statement where <code>current_region++</code> occurs...  please help me, thank you</p>
  
  <pre><code>-(void)planetRotation:(UIView *)planet average:(float )time1 perihelion:(float )time2 aphelion:(float )time3 region:(int ) current_region
  {
      current_region = 0;
  
      [planet.layer removeAllAnimations];
  
      if (current_region == 0 || current_region == 2)
      {
          [UIView animateWithDuration:time1 delay:0.0 options: UIViewAnimationOptionTransitionNone
          animations: ^{ CABasicAnimation* rotationAnimation;
                         rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
                         rotationAnimation.toValue = [NSNumber numberWithFloat: M_PI * 2.0 /* full rotation*/ * time1 * 1 ];//multiply more to add speed
                         rotationAnimation.duration = time1/4;
                         rotationAnimation.cumulative = YES;
                         rotationAnimation.repeatCount =  HUGE_VALF;
              [planet.layer addAnimation:rotationAnimation forKey:@"orbit"];} completion:^(BOOL finished){current_region++; }];
      }
      else if(current_region == 1)
      {
          [UIView animateWithDuration:time2 delay:0.0 options: UIViewAnimationOptionTransitionNone
          animations:^{ CABasicAnimation* rotationAnimation;
                         rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
                          rotationAnimation.toValue = [NSNumber numberWithFloat: M_PI * 2.0 /* full rotation*/ * time2 * 1 ];//multiply more to add speed
                          rotationAnimation.duration = 15;
                          rotationAnimation.cumulative = YES;
                          rotationAnimation.repeatCount =  HUGE_VALF;
              [planet.layer addAnimation:rotationAnimation forKey:@"orbit"];} completion:^(BOOL finished){ }];
      }
      else if(current_region == 3)
      {
          [UIView animateWithDuration:time3 delay:0.0 options: UIViewAnimationOptionTransitionNone
              animations:^{ CABasicAnimation* rotationAnimation;
                          rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
                          rotationAnimation.toValue = [NSNumber numberWithFloat: M_PI * 2.0 /* full rotation*/ * time3 * 1 ];//multiply more to add speed
                          rotationAnimation.duration = 15;
                          rotationAnimation.cumulative = YES;
                          rotationAnimation.repeatCount =  HUGE_VALF;
              [planet.layer addAnimation:rotationAnimation forKey:@"orbit"];} completion:^(BOOL finished){ }];
      }
  </code></pre>