0
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

//  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount)
        external
        returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender)
        external
        view
        returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

contract Test{
     IERC20 public tokenAddress;
    constructor(address _tokenAddress) {
        // USDc = USDC(0x2058A9D7613eEE744279e3856Ef0eAda5FCbaA7e);
       
         tokenAddress = IERC20(_tokenAddress);
    }

   function checkSupply() payable public returns(uint){
        
        return tokenAddress.totalSupply();
        

        
   }
}
2
  • This one is correct way. I think the return should be returns(uint256)
    – Safi
    Commented Feb 21, 2023 at 15:59
  • Getting this error- { "error": "Failed to decode output: Error: hex data is odd-length (argument=\"value\", value=\"0x0\", code=INVALID_ARGUMENT, version=bytes/5.5.0)" }
    – 1111
    Commented Feb 21, 2023 at 16:32

2 Answers 2

0

Sorry! I did not see it properly before. The function you have checkSupply should be view function and not payable. Eg.

function checkSupply() external view returns(uint256){
    return tokenAddress.totalSupply(); 
 }
1
  • Then I am getting this error- The transaction has been reverted to the initial state. Note: The called function should be payable if you send value and the value you send should be less than your current balance. Debug the transaction to get more information.
    – 1111
    Commented Feb 22, 2023 at 4:11
0

You have to read from the totalSupply function from the proxy contract: https://etherscan.io/address/0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48#readProxyContract

USDC Etherescan Total supply

3
  • How to get totalSUpply using solidity?
    – 1111
    Commented Feb 22, 2023 at 4:13
  • Check out this question, along with my answer: ethereum.stackexchange.com/questions/121370/… Commented Feb 22, 2023 at 9:03
  • I don't want to use web3 or etherjs library, how to get the totalSupply using solidity?
    – 1111
    Commented Feb 22, 2023 at 10:53

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