msg.value 是如何發送的？

我想知道“msg.value”究竟是如何工作的，就像這個例子中取自https://solidity-by-example.org/hacks/self-destruct

當函式沒有參數時，存款函式如何要求 msg.value 等於 1 乙太幣？換句話說，這個合約/函式是如何接收 msg.value 的？msg.value 是在部署時發送的嗎？

   uint public targetAmount = 7 ether;
   address public winner;

   function deposit() public payable {
       require(msg.value == 1 ether, "You can only send 1 Ether");

       uint balance = address(this).balance;
       require(balance <= targetAmount, "Game is over");

       if (balance == targetAmount) {
           winner = msg.sender;
       }
   }

   function claimReward() public {
       require(msg.sender == winner, "Not winner");

       (bool sent, ) = msg.sender.call{value: address(this).balance}("");
       require(sent, "Failed to send Ether");
   }
} 

msg.value包含在交易中，您可以閱讀 Solidity 文件的這一部分：https ://docs.soliditylang.org/en/v0.8.14/units-and-global-variables.html?#special-variables-and-函式 因此，沒有理由將它包含在函式參數中。

引用自：https://ethereum.stackexchange.com/questions/128694