Transferring EOS within Smart Contract

Question

I'm building a Smart Contract that transfers EOS from my contract account to end user accounts.

I can not seem to find up to date and correct syntax for transferring EOS using eosio.token from within my contract.

All the info I can find, generally, references something like:

void Mycontract::yourcontract_action(account_name from,
                                      account_name to,
                                      asset quantity,
                                      string memo)
{
    eosio::transaction txn{};
    txn.actions.emplace_back(
        eosio::permission_level(from, N(active)),
        N(eosio.token),
        N(transfer),
        std::make_tuple(from, to, quantity, memo));
    txn.send(eosio::string_to_name(memo.c_str()), from);
}

It is using old syntax and does not appear to function as intended when I try and mold this to my contract.

Answer 1

Have you tried to replace the from - field with your accounts/contracts name? If you use _self this should be possible.

Checkout this answer from @Jeff Zheng.

If you merge both codes and update macros you get something like this (please correct the code if needed, I didn't compile it):

void Mycontract::yourcontract_action(account_name to,
                                      asset quantity,
                                      string memo)
{
    // maybe add some require_auth here
    eosio::transaction txn{};

    // where quantity should be something like this
    // asset quantity = asset( 10000, symbol_type(S(4, EOS)) ); // equals to 1 EOS

    txn.actions.emplace_back(
        permission_level{_self, "active"_n}, "eosio.token"_n, "transfer"_n, // replaced from
        std::make_tuple(_self, to, quantity, memo)); // replaced 'from'
    txn.send(eosio::string_to_name(memo.c_str()), _self);
}

And take care of the eosio.code permission like mentioned in the other answer.

Answer 2

You could use the following syntax as well:

transfer_tokens(buyer, seller, asset(tokensToTransfer, symbol("ABC", 4)), "transfer tokens to seller");

void market::transfer_tokens(name from, name to, asset quantity, string memo)
{
    token::transfer_action transfer("eosio.token"_n, {from, "active"_n});
    transfer.send(from, to, quantity, memo);
}