Where are the "headers" for a Swift dynamic library?

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1

So I am trying to understand the Swift build process, and I'm struggling to understand how exactly dynamic libraries are handled.

So for instance, in the C/C++ world, if I am linking against a dynamic library, I would need to link the build artifact (.dylib) and I would also have to specify the header search paths (-I argument) so that the compiler can understand the public interface of the library.

Is there a Swift analog to this? For instance, if I look at the .build/debug directory for a SPM package which produced dynamic library products, I can see the .dylib artifacts there, but it's not clear to me where the interfaces are defined.

2

In your example, the .swiftmodule files are the compiled interfaces (automatically extracted from the .swift files).

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3

Interesting, thanks! Do you know how it works for mixed-language products? So for instance, it looks like each Swift target gets a .build directory, a .swiftdoc and a .swiftmodule, but C language targets only get a .build with a .d and a .o inside. Would the "include path" for those modules be the include dir in the original source location?

4

Yes, exactly.

You can do build -v if you want to see the nitty details passed to each compiler.

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5

Cool, good to know. Thank you!