Catching panic! when Rust called from C FFI, without spawning threads
As of Rust 1.9.0, you can use panic::catch_unwind to recover the error:
use std::panic;fn main() { let result = panic::catch_unwind(|| { panic!("oh no!"); }); assert!(result.is_err());}Passing it to the next layer is just as easy with panic::resume_unwind:
use std::panic;fn main() { let result = panic::catch_unwind(|| { panic!("oh no!"); }); if let Err(e) = result { panic::resume_unwind(e); }}
Editor's note: This answer predates Rust 1.0 and is no longer necessarily accurate. Other answers still contain valuable information.
You cannot 'catch' a panic!. It terminates execution of the current thread. Therefore, without spinning up a new one to isolate, it's going to terminate the thread you're in.