Logs and Events

Logs are declared at contract scope and emitted with the log statement.

Log declarations

contract Ledger {
    log Transfer(indexed from: address, indexed to: address, amount: u256);
    log Paused();
}

Emitting logs

contract Ledger {
    log Transfer(indexed from: address, indexed to: address, amount: u256);

    pub fn send(to: NonZeroAddress, amount: u256) {
        let from: address = std.msg.sender();
        log Transfer(from, to, amount);
    }
}

Indexed fields

Use indexed to mark fields for efficient filtering in downstream tooling.

log Approval(indexed owner: address, indexed spender: address, amount: u256);