how to transfer a specific balance from a smart contract?

Question

Whenever someone buys a smart-contract the amount (in Wei) get stored in SC(Smart Contract) address(this) += msg.value.

Now I am trying to create a function to redeem the balance of the SC

function redeemInvTokens(uint256 _amount) public returns(bool){
    require(_amount <= amount, "you cannot redeem the more tokens");
    balanceOf[msg.sender] -= _amount;
    msg.sender.call.value(address(this).balance - (address(this).balance - _amount))("Transferred ether to financier");
    return true;
}

but its not transferring any amount to the msg.sender.

How to transfer the specific amount to the msg.sender? so I don't have to use address(this).balance - (address(this).balanace - _amount).

"so I don't have to use address(this).balance - (address(this).balanace - _amount)"??? This expression is equivalent to _amount, what brought you to the conclusion that you need to use it in order to transfer the specific amount to the sender? You can simply do msg.sender.transfer(_amount). — goodvibration, Jan 21 '20 at 08:28
Also, what is amount in require(_amount <= amount, ...)? You should post a working example. This symbol (amount) is not defined anywhere in your code. — goodvibration, Jan 21 '20 at 08:30
msg.sender.call.value(_amount)() it is not transfering any amount to msg.sender so i used msg.sender.call.value(address(this).balance)(). but, again i want to send specific amount to msg.sender thats why that calculation to determine. — iamsujit, Jan 21 '20 at 08:48
And on top of that of that, why not simply do msg.sender.transfer(_amount)? — goodvibration, Jan 21 '20 at 08:51
but isn't this method should be avoided after Istanbul update? — iamsujit, Jan 21 '20 at 08:53
That one I'm not sure of (I mean, I've never heard of, so it would be reckless of me to rule it out). AFAIK, this is the primary (and recommended) method for transferring ether from your contract to some address. — goodvibration, Jan 21 '20 at 08:56

CaptPython · Answer 1 · 2022-08-09T08:51:38.107

Here is the sample example

    // SPDX-License-Identifier: GPL-3.0
        pragma solidity >=0.7.0 <0.9.0;
    /**
     * @title SimpleVault
     * @dev Store &amp; retrieve Funds from the contract
     * @custom:dev-run-script ./scripts/deploy_with_ethers.ts
     */
    contract SimpleVault {
        address payable owner;

        constructor () payable {
            owner = payable(msg.sender);
        }

        function withdraw() public {
               payable (msg.sender).transfer(getBalance());     // Transfer to msg.sender
   OR
            // payable (0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2).transfer(getBalance());  // Transfer to a specific address
   OR
           (bool success, ) = address(0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2).call{value:getBalance()}(&quot;&quot;);
        require(success, &quot;Transfer failed.&quot;); 

}

        function getBalance() public view returns (uint) {
           return address(this).balance;
        }
    }

Mahesh Rajput · Answer 2 · 2020-01-21T06:30:56.460

0

You can use call with gas estimation.

for example,

require(address(receiverAdr).call.value(_amount).gas(35000)());

In your case:

uint256 transferableAmount = address(this).balance -(address(this).balance - _amount);
 require(msg.sender.call.value(transferableAmount).gas(35000)());;

edited Jan 21 '20 at 06:30

answered Jan 21 '20 at 06:03

Mahesh Rajput

1,211
7
17

but isn't this method should be avoided after Istanbul update https://ethereum.stackexchange.com/a/19343/50405 – iamsujit Jan 21 '20 at 06:25
Yes. but you don't mention the exact error msg or transaction hash of transferred amount so. Don't worry I have edited the answer. pls check and let me know. – Mahesh Rajput Jan 21 '20 at 06:32

how to transfer a specific balance from a smart contract?

2 Answers2