Attribute Macro ink::event

#[event]

Implements the necessary traits for a struct to be emitted as an event from a contract.

By default, a signature topic will be generated for the event. This allows consumers to filter and identify events of this type. Marking an event with anonymous = true means no signature topic will be generated or emitted. Custom signature topic can be specified with signature_topic = <32 byte hex string>.

signature_topic and anonymous are conflicting arguments.

Examples

#[ink::event]
pub struct MyEvent {
    pub field: u32,
    #[ink(topic)]
    pub topic: [u8; 32],
}

// Setting `anonymous = true` means no signature topic will be emitted for the event.
#[ink::event(anonymous = true)]
pub struct MyAnonEvent {
    pub field: u32,
    #[ink(topic)]
    pub topic: [u8; 32],
}
// Setting `signature_topic = <hex_string>` specifies custom signature topic.
#[ink::event(
    signature_topic = "1111111111111111111111111111111111111111111111111111111111111111"
)]
pub struct MyCustomSignatureEvent {
    pub field: u32,
    #[ink(topic)]
    pub topic: [u8; 32],
}