compare two CGPDFDictionary

Is the a way to compare two CGPDFDictionaries? There is a function memcmp, but it doesn't work for me, because dictionaries are in diffe开发者_运维问答rent memory cells.

Can you use the CGPDFDictionaryApplyFunction function ?

It seems like if you supply a callback function , it will be called for every key-value pair.

void CGPDFDictionaryApplyFunction (
   CGPDFDictionaryRef dict,
   CGPDFDictionaryApplierFunction function,
   void *info
);

So you can pass your second dictionary ( say dict2 ) as info. In your CGPDFDictionaryApplierFunction you can see if the current key being enumerated is also in dict2