Flutter, Android, rinf, Cargokit, Rust, C: Problem loading ndk standard C++ library about cargokit HOT 7 OPEN

The target (and minimum version) is specified in cflags (i.e. --target=aarch64-linux-android21). If you look at the aarch64-linux-android21-clang file it's just a wrapper that adds the --target argument.

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Also the linker error looks like you need to link with libc++, so a missing linker flag, but Rust doesn't use libc++ so I'd assume that whichever crate is compiling and linking c++ code should take care of that.

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Also the linker error looks like you need to link with libc++, so a missing linker flag, but Rust doesn't use libc++ so I'd assume that whichever crate is compiling and linking c++ code should take care of that.

The C library I am compiling is not compiling inside Rust itself, it is compiled in the build.rs file of my Rust crate but I am using the Rust std::process::Command crate to actually call the make and make install commands of the C library, passing to it the parameters needed for each Android arch.

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I think on Android you can either manually link with libc++_static.a, or have to include libc++_shared.so in your APK.

https://developer.android.com/ndk/guides/cpp-support#selecting_a_c_runtime

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The target (and minimum version) is specified in cflags (i.e. --target=aarch64-linux-android21). If you look at the aarch64-linux-android21-clang file it's just a wrapper that adds the --target argument.

Finally I verified our C library does not like the format of the compiler + flags from Cargokit, so I will set them manually from paths.

I see there is a env var called CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER, is it supposed to be used as the LD (linker) in the environment or similar?

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I think on Android you can either manually link with libc++_static.a, or have to include libc++_shared.so in your APK.

https://developer.android.com/ndk/guides/cpp-support#selecting_a_c_runtime

I actually included the libc++_shared.so in the APK, in the arm64-v8a folder, but somehow when is packaged into the APK the library loses all its symbols. On the other hand, if I copy same library to an aarch64 folder the symbols are kept, but of course Android does not use it.

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Finally I verified our C library does not like the format of the compiler + flags from Cargokit, so I will set them manually from paths.

I have no idea what that means. The --target argument is a clang argument, nothing to do with your library, unless there is no way to pass custom compile flags, which woould be very weird.

I actually included the libc++_shared.so in the APK, in the arm64-v8a folder, but somehow when is packaged into the APK the library loses all its symbols.

gradle strips libraries (there is a way to configure it not to at project level), but public symbols should not get stripped.

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