iphone is like a computer program that can call an external program like dll

iphone is like a computer program that can call an external program like dll?
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Only use static library file extension. A
Reply:
Since care was born in Unix, should be able to.
Reply:
Is absolutely possible, I give an example, if you use face recognition technology, then you can download as a development opencv library, this promising development iphone version, opencv is c / c + + development, then I was in Using this library in an iphone project, and very easy to do face recognition.