I'm new to Solidity and i have this function to send value from the user account to the contract. It increments the balance of the user and that info is stored in a mapping.
function sendMoney() public payable {
payable(address(this)).transfer(msg.value);
balance_received[msg.sender] += msg.value;
}
It compiles and i can deploy but when calling the function i get this message:
"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."
I have funds in the user account and i state in the function that it's payable. What am I missing?
Thanks
I have such function to transfer tokens from contract and i get error where shoudl i add payable and i dont really understand if withdraw will withdraw ethers or tokens?
function withdrawBalances() public nonReentrant {
uint share = _Balances[msg.sender];
_Balances[msg.sender] = 0;
msg.sender.transfer(share);
}
.withdrawBalances errored: VM error: revert. revert 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.
This error occurs when you try to send some Ether when calling a function that isn't payable. Set Ether value to 0 to avoid this. You can also allow a function to accept Ether by using the payable keyword.
function withdrawBalances() public payable {
...
}
I want to use Oraclize in Remix, to test it. I'm too stupid to use their examples.
How can I make this work?
From their Github I took the YouTube-Views code and copied it into Remix
pragma solidity >= 0.5.0 < 0.6.0;
import "github.com/oraclize/ethereum-api/oraclizeAPI.sol";
contract YoutubeViews is usingOraclize {
string public viewsCount;
event LogYoutubeViewCount(string views);
event LogNewOraclizeQuery(string description);
constructor()
public
{
update(); // Update views on contract creation...
}
function __callback(
bytes32 _myid,
string memory _result
)
public
{
require(msg.sender == oraclize_cbAddress());
viewsCount = _result;
emit LogYoutubeViewCount(viewsCount);
// Do something with viewsCount, like tipping the author if viewsCount > X?
}
function update()
public
payable
{
emit LogNewOraclizeQuery("Oraclize query was sent, standing by for the answer...");
oraclize_query("URL", 'html(https://www.youtube.com/watch?v=9bZkp7q19f0).xpath(//*[contains(#class, "watch-view-count")]/text())');
}
}
When I use the viewCount it returns:
0: string:
This happens with all the other examples aswell.
With WolframAlpha eg. I also get the following error:
transact to WolframAlpha.update errored: VM error: revert.
revert The transaction has been reverted to the initial state.
Note: The constructor should be payable if you send value. Debug the transaction to get more information.
Ok you don't see the answer like a normal result in Remix:
You have to go under settings and open the Oraclize plug in.
If you then deploy the contract and or click update, you get the result shown in the plug in.
This is my code in Solidity
pragma solidity ^0.4.17;
contract WithdrawalContract {
mapping(address => uint) buyers;
function buy()public payable {
require(msg.value > 0);
buyers[msg.sender] = msg.value;
}
function withdraw()public {
uint amount = buyers[msg.sender];
require(amount > 0);
buyers[msg.sender] = 0;
require(msg.sender.send(amount));
}
}
Below is the error i am getting. Not sure why it is asking for constructor
transact to WithdrawalContract.buy errored: VM error: revert.
revert The transaction has been reverted to the initial state.
Note: The constructor should be payable if you send value. Debug the transaction to get more information.
That's just part of the error message Remix shows when a transaction reverts, presumably because that's a common mistake people make.
In your case, that's not the issue. My guess would be that you're calling buy and not attaching any ether, so the require(msg.value > 0) is causing the transaction to revert. In Remix, make sure you have a non-zero "value" in the upper right.
I'm trying to change the state variable value of solidity, and test on the geth console, but the value of state variable is not changed.
The steps are as below：
1: Write a simple smart contract code by solidity as below
pragma solidity ^0.4.0;
contract SimpleStorage {
uint public storedData=99;
mapping(string => uint) balances;
function set(uint x) public returns (uint){
storedData = x;
return storedData;
}
function get() public constant returns (uint) {
return storedData;
}
function multiply(uint a) returns(uint d) {
return a * 7;
}
function setmapping(string key,uint value) returns(uint v)
{
balances[key] = value;
return balances[key];
}
function getmapping(string key) returns(uint v)
{
return balances[key];
}
function kill()
{
}
}
2: compile the code by the truffle, use command
truffle compile
3:start the geth, unlock account, and start the minner
4:deploy the smart contract
truffle migration --reset
and then I see the console output as below
Using network 'development'.
Running migration: 1_initial_migration.js
Replacing Migrations...
... 0x8ccf9e1599c2760ff3eed993be10929403e1faa05489a247a067f4f06536c74c
Migrations: 0xec08113a9e810e527d99a1aafa8376425c4a75ed
Saving successful migration to network...
... 0xedbf12715b736759e9d9297cbaaeb3151d95f478c2f1ee71bff4819d2dbb47e5
Saving artifacts...
Running migration: 2_deploy_contracts.js
Replacing SimpleStorage...
... 0xff5b00f9b14d8ecea4828c3ad8e9dbfa9d685bc0b81530fc346759d7998b060f
SimpleStorage: 0x96cf1e076f4d99a5d0823bd76c8de6a3a209d125
Saving successful migration to network...
... 0x3452a9e76b73e250de80874ebc3fd454724ebf6a15563bee0d5ba89b7b41909f
Saving artifacts...
which means the smart contract deployed to geth successfully
5: Then in the geth console, I set abi variable as below:
abi=[{"constant":true,"inputs":[],"name":"storedData","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"changeStorage","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"kill","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"getAll","outputs":[{"name":"","type":"uint256"},{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"x","type":"uint256"}],"name":"set","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"get","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"key","type":"string"},{"name":"value","type":"uint256"}],"name":"setmapping","outputs":[{"name":"v","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[{"name":"","type":"uint256"}],"name":"refrenceType","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"changeMemory","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"key","type":"string"}],"name":"getmapping","outputs":[{"name":"v","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"a","type":"uint256"}],"name":"multiply","outputs":[{"name":"d","type":"uint256"}],"payable":false,"type":"function"}]
6: Get an contract instant as below:
test=eth.contract(abi).at("0x2f3970e8e4e2f5ed4ccb37b0f79fe5598700e2f0")
7: Run the set()
test.set.call(22);
The out put is 22, which I think the state variable storedData was successfully set to the new value 22, but when I run below code to read the storedData,
test4.get()
the return value is still 99, which mean the value of storedData was not changed, beside use the uint to do the testing, I also tried the mapping, but the answer is as same as uint, I don't know if I was wrong in somewhere or the state variable is not allowed to be modified, could anyone help me?
Thanks.
From the question, this is the call that is not changing state:
test.set.call(22)
In order to change state, you must issue a transaction. A call(...) only tells you what would happen if you were to send a transaction. For more background, see: What is the difference between a transaction and a call?
So you can replace the above line with:
test.set.sendTransaction(22)
Alternatively, web3.js will automatically attempt to decide whether to use a transaction or a call. So in this case you can use simply:
test.set(22)
For more background on how web3.js decides, see: How does web3.js decide to run a call() or sendTransaction() on a method call?