Why .\wasmedge.exe --reactor .\add.wasm add -10 1 results in 4294967287?

[rgl]

While trying https://wasmedge.org/book/en/quick_start/run_cli.html#call-a-webassembly-function-compiled-from-rust on Windows 10 as:

.\wasmedge.exe --reactor .\add.wasm add -10 1

It returned an unexpected value of:

4294967287

Is this expected? From what I understood, the rust add example uses a rust i32 (signed integer), so this result is unexpected to me.