title: How can "memory cleaner" apps determine the amount of used memory on iOS?
body: <p>Every now and then "memory cleaner" apps bubble to the top of the download charts on the iOS AppStore, yet I am always puzzled: How can these apps figure out how much memory is used when they are sandboxed and can't access any memory outside of their process?
  I'm not an expert in memory allocation on C, so maybe the solution is obvious and I just don't know it but I am curious as to how this works/could work.</p>
  
  <p>Obviously the second question is how do they clean the memory once they have the count, I assume they just allocate a ton of heavy objects (eg. images) and thus force the OS to shut down other processes. Yet maybe there is a smarter way?</p>
  
  <p>Note, I am not talking about Cydia here, these apps are available on the regular AppStore and work on non-cracked devices with the official consent from Apple. As an example, here is the current top seller: <a href="http://iputzfrau.professional-apps.at/" rel="nofollow">http://iputzfrau.professional-apps.at/</a></p>