发送eth (transfer, send, call)

如何发送以太币？

您可以通过以下方式将以太币发送到其他合约

• transfer（2300 gas，抛出错误）
• send（2300 gas，返回布尔值）
• call（转发所有gas或设置gas，返回布尔值）

如何接收以太币？

接收 Ether 的合约必须至少具有以下功能之一

• receive() external payable
• fallback() external payable

receive()如果msg.data为空则调用，否则fallback()调用。

您应该使用哪种方法？

call2019 年 12 月后推荐使用与重入防护结合使用的方法。

通过以下方式防止重新进入

• 在调用其他合约之前进行所有状态更改
• 使用重入保护修饰符

pragma solidity ^0.8.10;

contract ReceiveEther {
    /*
    Which function is called, fallback() or receive()?

           send Ether
               |
         msg.data is empty?
              / \
            yes  no
            /     \
receive() exists?  fallback()
         /   \
        yes   no
        /      \
    receive()   fallback()
    */

    // Function to receive Ether. msg.data must be empty
    receive() external payable {}

    // Fallback function is called when msg.data is not empty
    fallback() external payable {}

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

contract SendEther {
    function sendViaTransfer(address payable _to) public payable {
        // This function is no longer recommended for sending Ether.
        _to.transfer(msg.value);
    }

    function sendViaSend(address payable _to) public payable {
        // Send returns a boolean value indicating success or failure.
        // This function is not recommended for sending Ether.
        bool sent = _to.send(msg.value);
        require(sent, "Failed to send Ether");
    }

    function sendViaCall(address payable _to) public payable {
        // Call returns a boolean value indicating success or failure.
        // This is the current recommended method to use.
        (bool sent, bytes memory data) = _to.call{value: msg.value}("");
        require(sent, "Failed to send Ether");
    }
}