The Drop Trait and Resource Cleanup

The Drop Trait and Resource Cleanup

Rust implements RAII (Resource Acquisition Is Initialization) via the Drop trait.

Custom Drop Implementations

struct ResourceHandle {
    name: String,
}

impl Drop for ResourceHandle {
    fn drop(&mut self) {
        println!("Cleaning up resource: {}", self.name);
    }
}

fn main() {
    let _r = ResourceHandle { name: String::from("NetworkSocket") };
    println!("Resource active");
    // _r drops automatically when main exits
}

Resources (file descriptors, sockets, database handles) cannot leak due to early returns or panics because drop runs deterministically on scope exit.