How can I cancel the deferred transaction in EOS after we push the deferred transaction in the blockchain

Question

I have a action which execute the deferred transaction . Let I send the delay of 20 days . If I want to cancel the deferred transaction before 20 days . Is there any way I can do this ?

This is my action which I push to deferred the transaction .

void second::send(account_name from , account_name to ,asset  quantity,string  memo,uint64_t delay) {
            eosio::transaction t{};

            t.actions.emplace_back(
        eosio::permission_level(from, N(active)),       
        N(eosio.token),
        N(transfer),
                std::make_tuple(from,to,quantity,memo)
            );
            t.delay_sec = delay;
            t.send(N(memo), from);
        }

transfer( account_name from,
                      account_name to,
                      asset        quantity,
                      string      memo  ){....}

transfer is my action that execute the transaction .

Answer 1

void send(const uint128_t& sender_id, account_name payer, bool replace_existing = false)

First parameter(sender_id) is the id of the deferred transaction. You can call cancel_deferred(sender_id) to cancel it.

See example in delegate_bandwidth on GitHub.