How to Handle Errors Across the FFI Boundary

Unsafe Ffi

2026-04-17T12:05:42+00:00

Prevent FFI panics from crashing your Rust program by wrapping calls in catch_unwind and returning Result types.

Handle errors across the FFI boundary by wrapping unsafe calls in Result types and using catch_unwind to catch panics before they cross the boundary.

use std::panic::{self, AssertUnwindSafe};

fn call_ffi_safe() -> Result<i32, String> {
    let result = panic::catch_unwind(AssertUnwindSafe(|| {
        // unsafe { ffi_function() } // Replace with actual FFI call
        42
    }));

    match result {
        Ok(val) => Ok(val),
        Err(_) => Err("Panic occurred in FFI call".to_string()),
    }
}