Add documentation mentioning stdin, stdout, and stderr file descriptors, and also preopen file descriptors, and mention that preopen file descriptors can be closed.
Allowing preopen file descriptors to be closed is a change from how Wasmtime historically worked, but I think it's more clear now that it's ok to let preopens be closed. We'll change Wasmtime accordingly.
Add documentation mentioning stdin, stdout, and stderr file descriptors, and also preopen file descriptors, and mention that preopen file descriptors can be closed.
Allowing preopen file descriptors to be closed is a change from how Wasmtime historically worked, but I think it's more clear now that it's ok to let preopens be closed. We'll change Wasmtime accordingly.
This addresses WebAssembly/wasi-testsuite#50.