When building static library in XCode (.a), the architecture you selected in build target does affect the result. For example, if you select a simulator and build the static library, then the library will contain only architecture for simulator use. If you select a real device / generic iOS device, then the library will only contain architecture for a real device.

This means that either you can run the app (includes the static library) on a simulator or real device. It cannot be both. You will have to switch the library .a binary.

Below we will introduce a method to create a .a binary for both architecture. The benefit is to provide ability to run the app (includes the static library) in both simulator and real device.

Create Library With Both Architecture

First, build the library using simulator and rename the .a file to xxx_sim.a. Then build the library using real device and rename the .a file to xxx_device.a

Now using the bash utility lipo to merge them together.

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lipo -create xxx_device.a xxx_sim.a -output xxx.a

👆 xxx is the name of the static library.

Run Script

If you want to automate the process with Run Script section in Xcode, there’s some useful post: