Add readme

README.md

@@ -0,0 +1,48 @@
+# IOTA SDK Native
+
+## TODO
+
+This binding wraps the IOTA SDK into a native, shared library.
+
+It can be referenced by other languages such as Go, C/C++ or C#.
+
+It exports the following functions:
+
+```
+init_logger
+binding_get_last_error
+
+call_client_method
+call_secret_manager_method
+call_utils_method
+call_wallet_method
+
+create_client
+create_secret_manager
+create_wallet
+listen_wallet
+
+destroy_client
+destroy_secret_manager
+destroy_string
+destroy_wallet
+
+get_client_from_wallet
+get_secret_manager_from_wallet
+```
+
+Generated C/C++ headers can be found under `bindings/native/headers`.
+
+Headers can be regenerated by running `bindings/native/bindgen.sh`. This requires [cbindgen](https://github.com/mozilla/cbindgen/).
+
+An example implementation in Go can be found [here](https://github.com/iotaledger/wasp-wallet-sdk/blob/main/wrapper.go).
+
+# Usage
+
+All strings need to be null terminated.
+
+All strings coming from the library need to be free'd by calling `destroy_string` after receiving and copying them.
+
+Any function that either returns a `NULL` pointer or `false` might have catched an error.
+
+This error can be obtained via `get_last_error`.