@nerditation Thank you so much for answering my question! Here is the command output and I see that libxml2.so.2 is missing in the ldd output, yet it is available in the system and it shows in the output from Python. I'm sorry I don't understand anything about Rust at all and I don't know what LD_LIBRARY_PATH is and where and what value I should set it to.
Python 3.7.3 (default, Oct 31 2022, 14:04:00)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from ctypes import *
<CDLL 'libxml2.so.2', handle 958ab0 at 0x7fffff9fc1d0>
It looks like libxdrk-x86_64.so depends on libxml2.so but doesn't declare this dependency using DT_NEEDED. The xdrk rust crate does add a dependency on it to fix this, but if it is opened with RTLD_LOCAL as python's ctypes module does by default, libxdrk-x86_64.so still won't be able to find libxml2.so. I'm not a python expert, but I you could try CDLL(DLLNAME, mode=RTLD_GLOBAL) or something like that instead of cdll.LoadLibrary(DLLNAME)
You should first load libxml2 into your program using the RTLD_GLOBAL mode and only then load libxdrk.
from ctypes import *
dll = "/path/to/libxdrk-x86_64.so"
# first do this
# now the load of libxdrk should succeed
xdrk = cdll.LoadLibrary(dll)
# now you can call the functions defined in src/bindings.rs
# like open_file, etc
filename = "./testdata/path/to/testfile.drk".encode("utf-8")
xdrk.argtypes = [c_char_p]
ret = xdrk.open_file(filename)
# there will be some other errors like a missing XML file
# which you will need to solve
after a second inspection, I realized what OP was trying to load was not the rust binding, but rather the pre-built C library (which is copied to OUT_DIR by build.rs). the C library is a pre-built binary file(not built from source), it is under the aim directory of the repository. in such case, the added linker flag only affect rust code built by cargo.
so the issue actually has nothing to do with rust or cargo, this crate is just a wrapper for ffi bindings to their C library, rust code that depends on this crate builds and links just fine (but they don't have 32 bit support).
yes, manually load the missing library into global scope is a correct solution for such situation. you can achieve the same effect using LD_PRELOAD. another alternative is to build a wrapper library which is linked properly.
As @nerditation pointed out above, the .so file is pre-built. I assume the source code is not available, so you would have to contact the device manufacturer who designed the file format and ask if they have a shared library for ARM 64.