Ethereum

low-level call failed

I'm using the crowdsale contract (https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/crowdsale/Crowdsale.sol). I have deployed a detailedERC20 smart contract. When I send the ether to the crowdsale contract it shows me the following error: SafeERC20: low-level call failed When I use transfer() externally it works fine. computer Environment Ganache-cli ....

Ava Ava: yesterday

Ethereum

Loading truffle library in remix browser IDE

Besides writing smart contracts in the browser, I would also like to write my test in this IDE. Any suggestions how to load the truffle files in http://remix.ethereum.org? I appreciate your help! ....

William William: yesterday

Ethereum

Metamask Transaction does not appear in Ganache

I'm trying to call the storeQueryResults() function of my smart contract in the following way: storeInput: function(event) { var queryResultHandlerinstance; App.contracts.QueryResultHandler.deployed().then(function(instance) { queryResultHandlerinstance = instance; return queryResultHtandlerinstance.storeQueryResults(1, 2, "a", "b", { from: web3.eth.accounts }); }).then(function(result) { alert("success"); }).catch(function(err) { alert(err.message); }); }, }; Then, after confirming the transaction in Metamask, ....

Noah Noah: yesterday

Ethereum

Wrong order when calling a function to return a string

I have an array of strings in my Contract.sol: string[] messages; function getMessage(uint i) constant returns (string) { require(messages.length > i); return messages; } In my app.js, when the page is loaded I want to populate the page with all the strings. The relevant part of how that's done is ....

Ava Ava: yesterday

Ethereum

How to connect two truffle instances?

How can we connect two truffle applications with each other? E.g., if we have two metacoin applications, how can these two communicate with each other? ....

Mia Mia: yesterday

Ethereum

Adding token image into smart contract

can we directly add the token logo to the token smart-contract so that we can visualize it in Wallets and Exchanges and so that we don’t have to register it in another way Please help erc20 token standard ....

Olivia Olivia: yesterday

Ethereum

Should I convert Centeralised web app to Multichain because it is free to use and more secure compare to webapp?

I am Web app developer and exploring the blockchain technology from few months. I want to convert the live centralized WebApp to Decentralized Blockchain application. I know there is a high cost of Inserting data in to blockchain and there is 15 GB of data I want to put into ....

Mia Mia: yesterday

Ethereum

GeForce GTX 1070 - hashrate only 680 khash/s?

I am mining ArtByte and LiteCoin using a single GTX 1070 GPU. Everywhere on the internet I am reading that such a card can achieve 20+ MH/s. My card only gets as far as 680 khash/s. Am I missing something? How to investigate this issue? For ArtByte I am using: ....

William William: yesterday

Ethereum

sync function syntax

What is the difference between this syntax: beforeEach( async () => { ... }); and this one: beforeEach(async function() { ... }); Thanks ....

Elijah Elijah: yesterday

Ethereum

Truffle test javascript

I have a .sol contract: contract HelloWorld { string name="TEST"; uint number; function HelloWorld() { } function getName() returns (string) { return name; } function getNumber() returns (uint) { return number; } function setNumber(uint _number) { number = _number; } } And I'm trying to write a test in javascript ....

Evelyn Evelyn: yesterday