Rob (Nov 08 2022 at 14:46): Rob (Nov 08 2022 at 14:46):Hello, I'm trying to add an effect that executes a Command using Rust platform code. I got it working with just the command arg. But I wanted to pass in a list of args. But I keep getting a seg fault. My Effect definition is
exec : Str, List Str -> Effect (Result Str {})
and my Rust code is
pub extern "C" fn roc_fx_exec(cmd: &RocStr, args: RocList<RocStr>) -> RocResult<RocStr, ()> {
If I remove the args param from the code it compiles and runs fine. But with the RocList it seg faults.
Brendan Hansknecht (Nov 08 2022 at 16:14):My first gut reaction is that it is related to borrowing vs not borrowing(aka pass by reference or not). Should the RocList be &RocList?
Brendan Hansknecht (Nov 08 2022 at 16:15):Just seems strange that the string is passed by reference, but not the list.
Folkert de Vries (Nov 08 2022 at 16:24):no that is what the llvm codegen does at the moment
Folkert de Vries (Nov 08 2022 at 16:24):at least, internally
Folkert de Vries (Nov 08 2022 at 16:24):hmm the C interface might do something different. Worth a try
Rob (Nov 08 2022 at 17:39):@Brendan Hansknecht that worked thanks, but now I'm getting a seg fault trying to change the &RocList<&RocStr> to a Vec<String>
Here's the code I'm trying:
let rust_args: Vec<String> = args.as_slice().to_vec().iter().map(|x| x.as_str().to_string()).collect();
Brendan Hansknecht (Nov 08 2022 at 17:57):I think it should be &RocList<RocStr>
Rob (Nov 08 2022 at 18:27):@Brendan Hansknecht that did it! Thanks so much!
Notification Bot (Nov 08 2022 at 18:27):Rob has marked this topic as resolved.
Last updated: Jul 26 2025 at 12:14 UTC