All Questions

0
votes
0answers
6 views

DeclarationError: Identifier not found or not unique and Undeclared identifier

I am trying to create a crowdsale contract using zeppelin. But i am facing following errors. CrowdSale.sol:6:46: DeclarationError: Identifier not found or not unique. contract EdCoinCrowdSale is ...
0
votes
0answers
11 views

Function doesn't return any value but modify the data in the contract

I have a function that can retrive all data and one for retrive only not readed data. On Remix with JavaScrpit VM it's work, but on Remix with my private blockchain linked with web3 provider the ...
0
votes
1answer
14 views

Contract gives erc20 tokens based on an event, to an empty wallet

I have a new wallet address and no ETH. I want to be able to request an amount of 10 erc-20 tokens. Because I do not have any eth on this wallet, I want to be able to get the tokens onto my wallet ...
0
votes
1answer
18 views

Is it possible to transfer tokens from one Multisig Wallet address to another Multisig Wallet?

First, the multisign wallet has a number of tokens which I want to transfer to another Multisig wallet. Is it possible? If yes then how?
0
votes
1answer
22 views

CREATE / CREATE2 Verification

Where do I verify whether a contract has been created with CREATE or CREATE2, would I have to disassemble the contract and look for a CREATE2 opcode in the contract creation code?
0
votes
1answer
8 views

Unstructured storage proxies. Variables not being overwritten?

When using delegate call I was under the impression that storage slots declared in the proxy will be overwritten by the implementation. Unstructured storage implementations declare bytes32 variables ...
1
vote
1answer
26 views

Enigma “secret contract” and concealing transactions history: How is it possible?

Enigma protocol is a second-layer, off-chain network that aims to solve privacy issues in blockchain. However In Enigma blog, there is an article (Link to Article), explaining the secret contract, ...
1
vote
1answer
50 views

Deploy new contract through another contract function in Truffle

I have a function in my contract minter.sol that creates another contract etnX.sol: function createNewContract(string memory name, string memory symbol, uint256 _maxSupply) public onlyOwner { ...
0
votes
0answers
10 views

how to make geth light node connect to local full node

In my computer i have 1 full node, my full node is running using: geth --syncmode full --ws --wsport 8546. Is there anyway to create a light node to connect to that full node on the same local network ...
0
votes
0answers
14 views

Manage accounts in Remix Web3 Provider env connected to a TestRPC client node

When I run the TestRPC client (ganache-cli), it provides me with 10 different accounts and private keys along with a local server at localhost:8545 Available Accounts (0) ...
0
votes
0answers
16 views

Transaction receipt was not generated after 600 seconds for transaction:

I am sending a transaction through this code: txhash = careercertificate .createCertificate(id, fecha, nombre, rutalumno, instituto, rutinstituto, titulo, totalhash, ...
1
vote
1answer
6 views

web3.isConnected returns False web3.py

Here is the code I have: from web3 import Web3 infura_url = 'https://infura.io/project/MyProjectID' web3 = Web3(Web3.HTTPProvider(infura_url)) print(web3.isConnected()) The problem is that it ...
0
votes
1answer
14 views

why do i see input data in the transaction details when i didn't pass it as a data parameter

When I create a transaction like below App.contracts.Soccer.deployed().then(function(instance) { return instance.purchaseShoes(name, age, { from: accounts[0], value: value}); }).then(...
0
votes
0answers
10 views

Can ganache serve at a directory in addition to a port?

Using the ganache command line interface I can set a seed and a port: ganache-cli --seed 2048 --port 2020 Which serves to Listening on 127.0.0.1:2020 Can I get it to serve to a directory of my ...
0
votes
0answers
19 views

ALERT: Transaction Error. Exception thrown in contract code in Metamask [on hold]

I have deployed the contract in ropsten, when is put the package id from front end UI its showing the metamask error, i have increased the gas to fix this but even its showing the same error: ...
-1
votes
0answers
20 views

Error: Unexpected end of input [on hold]

I got an problem when i run truffle test, here my cmd: and here my js file: var DappToken = artifacts.require("./DappToken.sol") contract(DappToken, function(accounts) { var tokenInstance; ...
1
vote
0answers
7 views

Ocasional connection refused initializing web3

I have an ethereum web application using web3js 1.0.0-beta.34 on a private network. Most of the times everything works fine. Sometimes the connection to the node through a websocket provider fails ...
0
votes
1answer
19 views

Can I automate the truffle (smart contracts) test scripts?

As we all aware about smart contract testing using truffle framework. Currently, we are writing the test scripts either in solidity or in java-script manually. Is there any way so that I can auto ...
1
vote
0answers
13 views

Transaction sent from web3 cannot reached all transaction to network node

I used one node endpoint to interact with the network. While sending a transaction from web3.js 0.20 to ethereum network, transaction per second (TPS) I achieved is only 28 TPS. I have configured the ...
1
vote
0answers
24 views

Smart contract will not deploy to my private blockchain when using Remix IDE

So I'm a complete newbie and trying to deploy my first smart contract to a local Ethereum blockchain. I'm doing this on a Windows machine. I have created a private blockchain using geth, made an ...
0
votes
0answers
16 views

Blockchain-related Research Topic For Thesis [on hold]

So I'm about to start writing my M.Eng. thesis in a month and I would like to angle it towards a challenging topic related to blockchain technology. I'm passionate about security, smart contracts, ...
0
votes
1answer
25 views

ERC721-OpenZeppelin: This contract does not implement all functions and thus cannot be created

I know there are already a lot of topics that deal with the problem but their solutions didn't work for me. this is the code: pragma solidity ^0.5.2; import "https://github.com/OpenZeppelin/...
1
vote
0answers
15 views

How to create new contracts (contract2a, b, c, etc) from a function in contract1 and then access the new contracts

This is my first question here and I’ll try to keep it specific. I have a “Baker” contract that has a function that makes a new “Cookie” contract. I deploy it in Remix and have problems interacting ...
0
votes
1answer
22 views

map multikey how-to?

I'm trying to create a map whose key is composed of two bytes32 keys. I've tried with tuples-keys and struct-keys but both are rejected by the compiler. I'm also thinking about "hashing" both keys ...
0
votes
0answers
7 views

quorum-maker-no web UI is exposing on any host ports after creating nodes

Im trying to deploy contract using quorum-maker, I've followed every step as mentioned in wiki, but still not able to connect web UI and have no idea where Web app is deployed(in wiki. http://10.50.0....
1
vote
1answer
18 views

Can Qorum Blockchain supports partail transaction encryption?

My use case is that we need to protect sensitive data in the transaction in blockchain. But we want to open other data in the same transaction to the public, Can Quorum support the above mentioned ...
0
votes
1answer
30 views

Why does updating an external variable results in an error?

I'm trying to update a variable within an external contract. My 2 contracts are as follow: pragma solidity ^0.4.25; contract MainContract { string public variable1; function setVariable1(string ...
0
votes
1answer
19 views

How could Compound's interest accruing every block? How's that implemented?

Here I'm referring to https://compound.finance, which is quite an awesome product. One thing inspires me most is that the interests accrued in Compound are updated per block. How's that even possible?...
0
votes
0answers
11 views

Calculating the PPS reward

I'm trying to write a DAPP to calculate estimated rewards of miners. What is the right way to calculate PPS reward? Single Share Reward => (portDifficulty / networkDifficulty) * BlockReward Total ...
0
votes
1answer
22 views

Is this implementation of multisig2of3.sol secure? [on hold]

I implemented multisig 2 of 3 contract. Please give me feedback on codestyle, security and usability. On codereview there is only two solidity questions, so I posted here. see on github pragma ...
0
votes
1answer
19 views

Solidity, problem with bytes decoding

back with another question towards solidity Guru's. I am trying to call a method which takes bytes array as an input, but either I am encoding this parameter wrongly or decoding it wrongly. Solidity ...
0
votes
1answer
17 views

Custom miner checks in a private chain?

I have used the ideas from the link [1]How to make miner to mine only when there are Pending Transactions? in my private chain. I have a couple of questions, - How can I add custom code on the miners ...
0
votes
0answers
19 views

are current ethereum opcodes prices in pyethereum updated?

I am not an expert in opcodes for Ethereum, but i am wondering if their prices here [https://github.com/ethereum/pyethereum/blob/develop/ethereum/opcodes.py] are updated as the latest version used by ...
0
votes
2answers
18 views

Create token with address and fields

I would like to know if it is possible to create tokens that have a different address or id for each one. I need to create a series of "objects" with the same structure but with the values of ...
0
votes
3answers
18 views

Is it possible to make multiple function calls in a single transaction?

Say I want to make a transaction that calls foo() and the calls bar() afterwards. I could make a contract that calls them both in sequence, but that's kind of a pain. Is there a way to just call both ...
-1
votes
0answers
23 views

solidity programming in blockchain [on hold]

pragma solidity ^0.4.17; import "./ERC721/ERC721Token.sol"; /** * @title Repository of ERC721 Deeds * This contract contains the list of deeds registered by users. * This is a demo to show how ...
0
votes
1answer
29 views

Sending private key to server side

I am trying to build new Dapp application for our startup by using web3j , I am facing an issue with signing the transaction from server side , because i need to know the private key for the client (...
0
votes
1answer
14 views

How to send ERC20 Token?

I try to send Token based on Erc20. and I can send Ether and something function but i dont know how to use transfer function in javascript like that. function transfer(address _to, uint256 _value) ...
0
votes
0answers
27 views

Etherscan API “Error! Missing Or invalid Module name” [on hold]

I am using Etherscan.io APIs to verify my smart contract. I have a very simple smart contract to test the verification process, here it is - pragma solidity ^0.5.0; contract HelloWorld { ...
0
votes
1answer
32 views

Rewriting msg.sender.call.value(amount)() into one under version 0.5.x

I want to rewrite - bool ok = msg.sender.call.value(amount)(); - emit WithdrawalEther(msg.sender, amount, ok); into - (bool ok, bytes memory returnData) = msg.sender.call(abi....
0
votes
1answer
17 views

Retrieve the status of a contract by its creator

In a situation where there are multiple contracts stored in different blocks, is there any method to retrieve the status of a contract through its owner's address? (e.g. in my situation, each person ...
0
votes
2answers
16 views

Std set in solidity?

Is there any way or library to have a set in solidity that can be iterated like C++'s std::set? library Set { // We define a new struct datatype that will be used to // hold its data in the ...
0
votes
1answer
15 views

Can't connect Android app to Ganache using retrofit

I'm have deployed contracts on ethereum blockchain. I have ganache running on server I'm tring to connect to it from android with this code: private BlockChainService() { Retrofit retrofit =...
0
votes
1answer
14 views

Error: sets the total supply upon deployment

Please help ! When i try to run test from truffle, i got this problem, here my test js code: var DappToken = artifacts.require("./DappToken.sol") contract(DappToken, function(accounts) { it ('...
0
votes
1answer
30 views

How to determine if an internal transaction creates a new contract?

I'm working on programmatically analyzing smart contracts and I need a way to determine if an internal transaction is creating a new contract. Can this be done by looking at the event logs? Anyone ...
0
votes
1answer
19 views

Does increasing the size of array guarantees that new elements are initialized to default value?

I get an error when trying to initialize array inside a struct of an array and I find this post: https://github.com/ethereum/solidity/issues/4115 . It seems that I have to work around by increasing ...
0
votes
1answer
15 views

why do ERC223 supporting contracts need to maintain the token list

I was going through ERC223 and read that contracts which are supporting any erc223 token contract should maintain the list for them so that they can accept only those tokens. Is that the correct ...
0
votes
2answers
23 views

eth.sendTransaction successful or not?

I sent 1 ETH on a private chain from node1 to node2. >eth.sendTransaction({ from: "0x30278b135d0f5c10eb0684ff18bfd84912ae0f2b", gasPrice: "5000000000", gas: "21000", to: '...
1
vote
1answer
40 views

Empty value (0x) returned from contract web3j

I'm trying to deploy a very simple contract on Windows 10, using Web3j 4.2.0. I've created an account using Mist. I've set up one local ethereum node (using geth) on my machine and I'm able to deploy ...
1
vote
3answers
50 views

How to get “deep” values in javascript?

I am currently building a project where the users can referr other persons. Now let's say I have a user who has only 2 referrals but those 2 also have another 2, then again 2 etc. and that for much ...

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