title: Execute function every X minutes in background doesn't work
body: <p>I use this code to execute function every X minutes:</p>
  
  <pre><code>- (void)executeEveryOneMinute
  {
      [self myFunction];
  
      dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(60 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
  
          [self executeEveryOneMinute];
  
      });
  }
  </code></pre>
  
  <p>And it works when app is in foreground.<br/>
  But when app goes background it doesn't work anymore.<br/>
  When I return app to foreground again it execute function once.<br/>
  And continue to call function every minute again.<br/><br/>
  So how to make this to work in background too?</p>