iOS: Clarify different Search Paths

Framework search path: where to search frameworks (.framework bundles) in addition to system frameworks paths. Not used very much in iOS development, officially there is no developer iOS frameworks.

In Mac development, it's set automatically if you drag a 3rd party framework into the project. Otherwise, just set it to the container directory where you saved the framework.

In xcconfig files you use this variable:

FRAMEWORK_SEARCH_PATHS = "/path/to/frameworks/container/directory"

Header search path: where to search for header files (.h files) in addition to system paths. Usually you'll need it if you are using a 3rd party library. Set it to the directory where you have the header files. If you use a directory to include the header (example: #import "mylibrary/component.h") set it to the parent directory.

In xcconfig files you use this variable:

HEADER_SEARCH_PATHS = "/path/to/headers/container/directory"

Library search path: where to search for library files in addition to system paths. Xcode will set it automatically if you drag a library (.a files) into the project. To set it manually, use the directory where the library is located.

In xcconfig files you use this variable:

LIBRARY_SEARCH_PATHS = "/path/to/libraries/container/directory" 

All three can hold a list of paths, with quotes, separated by space.

These are used for searching for Frameworks, Header files, or Libraries that are not in the system search paths (like QTKit.Framework, standard C++ header files, etc).

My most common use for this is using the boost header library (*.hpp) files in my code I add the relative path "../lib/Boost/1.46.1" to the Header Search Path.

I find it better to add this at the project level instead of in each target. That way the targets inherit this and it only needs to be changed in one place if I update the version of boost.