Issue implementing an approveUSDT function in a contract

Solidity Programming
#1

Hello! Iā€™m experimenting with a presale contract based on the BSC testnet, and in the contract Iā€™m attempting to achieve the purchase of my own token with USDT.

Using my own code within the contract itself, I cannot get approval to go through properly for the presale contract to spend my USDT on behalf of me.

However if I use the approve function within the ā€œwrite contractā€ section of the USDT token on BSCSCAN, it does work - and I can buy tokens after approval went through.

While approval via BSCSCAN works, this would not be convenient for further users of the contract. So I would need working code within the contract itself to cover approvals, but I havenā€™t been able to get any working as expected.

Example of the approval code:

function approveUSDT() public {
        
        IERC20 usdtToken = IERC20(0x337610d27c682E347C9cD60BD4b3b107C9d34dDd);

       require(usdtToken.approve(address(this), tokenAmount), "Approval failed");
        
       emit ApprovalSuccessful(msg.sender, tokenAmount);

}

What am I missing here? Thanks!

#2

Hi @HATOKEN

What is the error you are seeing when you run your code?