CODEWITHSUNDEEP
iosswiftxcodeswift-package-manager
David Hoerl
David Hoerl

Reputation: 41642

How to construct a Swift Package that links to a local (not system) library?

I must have read over a dozen posts on possible techniques to link a local library into my Swift Package. Specifically, my package depends on libturbojpeg.a, which most users won't have installed anywhere. Even if they did install it (there is a DMG), I'd have to go through hoops to make sure I was linking in the correct version. I finally found a post in the Swift Forums that basically says you can't do it now.

It appears that the only way to link it now is using .linkerSettings(LinkerSetting.unsafeFlags(..., but if you use that your package can't be managed by Xcode (see above link, and I even tried it and verified it cannot be used).

Is there some kind of workaround that allows me to distribute my Swift Package with the library?

Upvotes: 0

Views: 873

Answers (1)

David Hoerl
David Hoerl

Reputation: 41642

In my Package, I created a directory "Libraries" and added my library there.

I discovered that Xcode 11 places included Swift Packages in a specific location in the Derived Folders directory. This means that it is possible to tell Xcode where to find it during the link phase.

My Package has these instructions in it for users:

1) Add the Package using Xcode->File->Packages with the URL of https://github.com/dhoerl/

2) Open the app's Project Build Phases, and from the Package shown in the left file pane, drag the Libraries/.a file into the link phase. It will appear just above the that should already be there

3) In Application Build settings, under library search paths, add: "$(BUILD_DIR)/../../SourcePackages/checkouts//Libraries"

Build and run! Voíla - works like a charm!

Note: obviously this is somewhat fragile, Xcode 12 could change how packages are managed, but its possible by then that the Swift Package Manager will support linking of local libraries (its mentioned in the above link.)

Upvotes: 2

Related Questions