Library not found when statically linking to Draco

[ClayQAQ]

I have compiled draco by using “$ cmake ../ -G Xcode” . And I also got “libdraco.a” from Debug folder，and put libdraco.a into the Xcode But xcode show "Library not found for -ldraco", Would you mind helping me?

[warrenm]

You have at least two options for linking to a static draco library.

If you want to use linker flags (-ldraco) to link, you also need to specify the directory where the .a file is located in the target's "Library Search Paths"; Xcode doesn't automatically search the project directory recursively.

On the other hand, you can add the library to the target's Link Binary with Libraries build phase; this should automatically note the path to the library without needing to specify it elsewhere.

[ClayQAQ]

Thank you for your reply. But the way you said doesn't work. In fact，I've done both of these options. I wrote the path of "libdraco.a" on the "Library Search Paths", and also add the library to the target's Link Binary with Libraries build phase. I wonder if I compiled draco library incorrectly. No draco header file found after compilation. Here is my Xcode's configuration：

And here is the draco library I builded:

[warrenm]

The search path should be a directory, not the path of the library file itself.

[ClayQAQ]

Understood, you're right. I have already run the Draco library, but the "libdraco.a" library is 21.3MB in size. Is it too large? We only need the decoding functionality. When compiling Draco, can we make it as small as possible? How did you do it?

[warrenm]

I think you can reduce it to a few MB per architecture if you compile it in release mode optimized for size. If you want a prebuilt package and you’re comfortable with adding an SPM dependency, I made DracoSwift for exactly this purpose.

[ClayQAQ]

Thanks I'll take a look

[ClayQAQ]

I recompile libdraco.a to 2.7MB in release mode. Can I extract only the decoding module and further compress the library's size?

[warrenm]

You can do whatever you want if you’re compiling from source. Keep in mind that since you’re statically linking, though, that your final binary size won’t increase by the size of the compiled library; it’ll only increase by the size of the functions that are actually used by the app.

[ClayQAQ]

You mean The Xcode compiler will optimize and discard the portions of static libraries that we are not using, isn’t it? So I don't have to mind the size of the static library embedded in xcode.

[warrenm]

It's a bit of a subtle art that I don't fully understand, but if you think of a static library as an archive of object files, under certain optimization settings, a linker can recognize which sections of a static library are never referenced and omit them from the final binary. You could probably produce a smaller static library to begin with by manually including only the functionality required by your app, as DracoSwift is intended to be a fully general distribution of Draco.

[ClayQAQ]

Thanks, but manually selecting static libraries is a bit of a hassle.

[warrenm]

Okay, well, at this point you know your options, and you can decide how to proceed.