NDK need gnustl_static std::string instead of std::_ndk1::string

Question

I am hooking an existing library that is compiled using gnustl std::string instead of libc++ std::_ndk1::string. If I try to set or access these strings I just get garbage. How do I convert my std::string to std::_ndk1::string and vice versa in my hook application?

I cannot compile my hook with "-DANDROID_STL=gnustl_shared" because it no longer exists and other libraries in use require libc++.

The documentation mentions this https://developer.android.com/ndk/guides/cpp-support "The various STLs are not compatible with one another. As an example, the layout of std::string in libc++ is not the same as it is in gnustl" which is exactly the problem.

Answer 1

To use gnustl, you could compile all your native code with NDK r.17 or older. This is a dangerous path, because many important bugs, including security-related, have been fixed since then.

Another unsupported (and not recommended) way to deal with your problem is to get the gnustl sources from NDK r.17 and compile them with the latest NDK version.

Your best option is to have all your dependencies rebuilt with a recent version of NDK and its c++_shared runtime library.