What exactly is an Target in Xcode?

I was always wondering what's up with those Targets? What is it all about? What's the point of that? I never had to fiddle around with th开发者_运维问答em, but obviously I can. Why should I want that, and what can I do with them? What's their purpose?

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Each project can build multiple executables or libraries or call out to a makefile or shell script to build "stuff". Each one of these is a Target.

One iPhone project I have includes a separate target for each static library in my home grown SDK and a shell script target to build the Doxygen docs. Another project includes two targets, one for the app as used by general users, one for an administration & management edition.

In the first example, I need to build each library then link all the static libraries into an SDK test application, so my SDK Test App depends on all the library targets (but not the docs, since I don't need to constantly regen them.)

In the second example, the management and the general versions of the app share a considerable amount of code and resources. When I change one, I want to change them both.

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The target is something like a "blueprint". It includes rules that tell the compiler what to do, which sources should be compiled, which files should be copied into the application bundle, which libraries should be linked.

If you want to make a Free-Version of your app one way to do so is to add a new target.
Of course you could just duplicate the whole project but then you had to keep those in sync if you change some code. Using a different targets makes this a lot easier.