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The ERC20 Token Standard is a set of 8 functions to be included (in an agreed upon language) in a smart token contract in order to enable interoperability across multiple interfaces and dapps. These functions relate to (1) how tokens can be transferred (2) how to access data about the token, and (3) ...

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Error encountered, bailing. Network state unknown. Review successful transactions manually. exceeds block gas limit

I am trying to deploy my crowdsale contract using "truffle migrate --network ropsten". I encounter this problem "Error encountered, bailing. Network state unknown. Review successful transactions ...
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2answers
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Type address is not implicitly convertible to expected type contract ERC20

I am trying to compile my crowdsale contract and get this error: " TypeError: Type address is not implicitly convertible to expected type contract ERC20. token = ...
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2answers
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Smart contract - require token balance in constructor

I want to build a smart contract which can only be constructed, if there's an amount x of a specific ERC20 token available to spend for this contract. So either the contract has to be allowed to spend ...
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2answers
32 views

Is USDT ERC20 token or omni?

for USDT, Is there any wallet or holding usdt coin? Is it is erc 20, what is the contract address? Which USDT popular, omni or erc20? these two equal? Is there any USDT api to use? or USDT payment ...
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1answer
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Openzeppelin ERC20/StandardToken.sol changes some state variable to private

I made token based on Openzeppelin ERC20. Few days before, StandardToken.sol which I imported changed some of its state variables(total supply_, balances) from internal to private. github history ...
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1answer
18 views

My transaction is pending and it seems like doesnt execute the transaction at all?

I wanted to transfer ERC20 tokens from MEW to another ERC20 token wallet. It seems like not moving. Now my transaction is pending and it doesn't showing up in myetherwallet as a pending status. Can ...
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2answers
26 views

ERC20 Smart Contract not visible on Ropsten

While trying to deploy my erc20 contract on ropsten,I am not able to see transaction at https://ropsten.etherscan.io Steps I followed 1) My Config file : networks: { development: { host: "...
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3answers
32 views

Make command to send erc20 token with a different paid address

I want to send 100 ERC tokens from address A to address B but in address A there is no eth to pay fees, I want address C to pay for this transaction, how to do, please help, thanks
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1answer
25 views

How can I redeploy my ico/erc20 token from Rinkeby to the main Ethereum network?

If you know and have a tutorial please attach the link in this thread. My token on Rinkeby looks like this: https://dappuniversity.github.io/dapp_token/
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0answers
21 views

ERC20 library - connection refused

I installed the ERC20 and the EthereumRPC libraries on my shared hosting at Namecheap (which took quite some effort as I couldn't use Composer, but I got that part to work). Now when I try to connect ...
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2answers
19 views

Function owned() is public

Since function owned is public, does it mean anyone can externally call it and own the contract as msg.sender? contract owned { address public owner; function owned() public { owner =...
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1answer
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Why does the ERC20 Token wiki example subtract the balance of address(0) to calculate total supply?

When reading the ERC20 Token Standard in the Wiki, I've noticed that in its Sample Fixed Supply Token Contract, the value of balances[address(0)] is subtracted from the contract's total supply to ...
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2answers
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Whitelist.sol - Getting the array of whitelisted addresses

I am writing a token that inherits from Whitelist.sol. I would like to write a function that returns an array of addresses that are whitelisted. It must be something along the lines of function ...
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1answer
21 views

Getting compilation error when trying to use openzeppelin for erc20 token

I installed Openzeppelin framework and created a simple token sol file. pragma solidity ^0.4.24; import "node_modules/openzeppelin-solidity/contracts/token/ERC20/MintableToken.sol"; contract SToken ...
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1answer
26 views

why out of gas when gasLimit is not reached

https://etherscan.io/tx/0x43f39829b3a48c4146808b12489e01bdb5dfa32d5b49514298339a719e538c09 this tx failed, and the msg shows the cause is: out of gas, but Gas Limit is 520000, while only 86056 Gas ...
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1answer
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What does it mean that if particular wallet has more of particular erc20 token than ever recieving it via transactions? How dit it get there?

I know this is basic question, but would like to know answer anyway :-) Example is here: https://etherscan.io/token/0x4dc3643dbc642b72c158e7f3d2ff232df61cb6ce?a=...
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1answer
22 views

Wrapping ETH calling the WETH contract

I am trying to automatically wrap ETH when a user deposit ETH on my dapp. Therefore I am trying to call the WETH contract (on the Kovan Testnet for now). I wrote this code : WETH9_ WETH = WETH9_(...
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0answers
22 views

Web3JS Batch transactions

So I have a script that distributes erc20 to multiple wallet addresses, but it creates a individual transaction for each address. Is it possible to group this transactions and save on gas cost? I ...
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0answers
14 views

How does the initial token distribution look like on the blockchain?

How to identify the initial token distributions for this token? Where to find them and how do the transactions look like? Also, is it possible to identify who contributed to receive the ERC20 tokens?...
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1answer
22 views

How to add ICONS to our tokens on test network? [closed]

I have seen several questions about adding icons to the existing Tokens in main net. But is it possible to add icons and other information to tokens on test network ?? ((just for testing purpose)...
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1answer
22 views

How do Token transfers, the associated token contract transactions and ERC20 token txns fit together?

Looking at Quantstamp token as an example it contains a list of transfers: Similarly the associated contract also has "Transactions" and "Erc20 Token Txns", however they all seem to be different. ...
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1answer
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Extremely low token supply after token created on Tokenfactory via Metamask

I used the parameters in the picture below to create a token for our organization, but instead of showing the desired token supply of 1000000000 & 18 decimals (similar to, say, the MDT token for ...
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1answer
27 views

How to send multiple ERC20 tokens

There are about 2k ethereum addresses I'm supposed to send my ERC20 token to. Doing this manually is a no no. I've searched to and fro to no but most of the tutorials are not detailed enough. So can ...
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2answers
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The last line (line 247) in my ERC-20 code has a “ParserError: Expected Pragma, import directive or contract interface”. How do I solve this?

What measures do I take to solve this? I am currently on Compiler version 0.4.24 and this error shows up multiple times in my code which I solved by inserting a bracket. Now it is at the end of the ...
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1answer
22 views

Asset Tokenization: How to issue security tokens for different companies and trade them on the same exchange market?

Premise: I’m still learning here so I apologize if my question is too basic. Let's suppose that someone is developing a digital market for equity shares using blockchain (because it could save huge ...
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1answer
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What does this error mean and can someone please provide the answer? It keeps saying Parser error on the burn function

Click Here for the image. ` pragma solidity ^0.4.25; contract owned { address public owner; function owned() public { owner = msg.sender; } modifier onlyOwner { ...
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2answers
26 views

What is the currency of the field “value” in ERC20 transfers?

I'm trying to understand every fields in an erc20 transfers. But I don't find any informations about the currency of the value field : https://etherscan.io/tokentxns Can someone explain me ?
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25 views

Can't deploy contract due to the error: gas required exceeds allowance or always failing transaction

I'm trying to publish the contract below using remix, but I can not because of the error: gas required exceeds allowance or always failing transaction. I did not make any changes to the openzeppelin ...
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1answer
19 views

Reentrancy Attack on Crowdsale contract with transferFrom method?

I'm trying to build a crowdsale contract for an existing erc20 token. This the function allows users to buy the token: function buyTokens(address _beneficiary) public onlyApproved(_beneficiary) ...
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1answer
23 views

why this contract can successfully do the transfer()

I am reading the source code of this erc20 token: https://etherscan.io/address/0xfdfd5db568f2ecf9b06a16116b9201b0500735b4#code the code is like this: contract VelixIDToken is ReleasableToken, ...
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1answer
11 views

How to get contract address wit htruffle?

The token .sol: // ---------------------------------------------------------------------------- // '0xBitcoin Token' contract // Mineable ERC20 Token using Proof Of Work // // ...
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1answer
14 views

How to set the total supply for an ICO contract

I'm trying to create a test ICO contract (simply for the purpose of learning about blockchain etc). I have followed a tutorial and produced the following contract. The total tokens supplied to the ...
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2answers
20 views

Reject TransferOwnership Smart Contract Solidity

I found the following code for solidity smart contracts ownership purposes. contract owned { address public owner; function owned() public { owner = msg.sender; } modifier ...
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0answers
16 views

How can I create a smart contract which airdrops ERC 20 tokens to user?

I want to create a smart contract which airdrops ERC 20 tokens to registeres & verified user. What would be the procedure for this? Is it necessary for me to pay the gas fees for airdropping ...
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0answers
15 views

How to interoperate a public ERC20 token with a private network data assets?

A user should be able to purchase a digital asset, which resides in a private blockchain, with an ERC20 token, which is on mainnet. Each asset has it's own unique price tag. [Assets- in private ...
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1answer
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Is it possible to burn the balances of a contract from another contract?

Imagine the scenario in which contract A has in its possession 1000 tokens (of the contract itself). is it possible to create a second contract and burn the tokens of contract A? contract ContractA ...
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transaction never arrive etherscan [duplicate]

Sent some tokens but never arrive https://etherscan.io/tx/0x12a1eaf69bd798fa03c33e3323b83e99ac5fc46dad7e621b8da0edfcd64d54a5
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0answers
16 views

Showing me error Allocation failed - process out of memory when compile this contract

The contract is the following https://github.com/etherdelta/smart_contract The error. C:\Users\mirror\Desktop\smart_contract-master>truffle test compile <--- Last few GCs ---> [1668:...
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1answer
10 views

Error to compile this contract

The contract is [{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_value"...
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22 views

How does online wallets handle ERC20 tokens behind the scenes? [duplicate]

Described in the title: How do online wallets handle ERC20 tokens behind the scenes? Or centralised exchanges in that matter. Are they simply communicating with the ethereum blockchain to generate ...
1
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1answer
20 views

My Transaction is pending for over 20 hours now - initiated a call to the transfer function using Web3

I'm making a call to the transfer(address _to, uint256 _value) function within the contract through Web3. Here's my code; var Contract = web3.eth.contract(ContractABI); var ContractHandle = Contract....
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@param _toAddresses quesion

Is there anyway to increase the * @param _toAddresses The addresses of the recipients (MAX 255) * @param _amounts The amounts of tokens to be transferred Instead of 255, can it be increased to ...
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1answer
42 views

multiple transfer?

First of all, hello. we will write a token for a project we have developed. We are creating new tokens, we want to write a simple contract on remix ethereum. We will distribute a large portion of the ...
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2answers
34 views

The contract code couldn't be stored, please check your gas amount. [Zeppelin, Truffle.js, Ropsten]

I am having some problem with deploying the simple Token Contract to Ropsten network. Error is "The contract code couldn't be stored, please check your gas amount". I tried to change Gas values ...
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1answer
21 views

Can security tokens (ST-20) and utility tokens (ERC-20) exists on same blockchain?

I am trying to build a dApp in which the functionalities of the dApp can be accessed by utility token but in the same app I wish to tokenize the securities as well. Can my utility tokens and the ...
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1answer
21 views

How to exchange two different ERC20 compliant tokens directly?

In my Dapp, I have two different ERC20 tokens: say, ABCToken and XYZToken. A user could give 10 ABCTokens to an account and in return should get 5 XYZTokens. Is it possible to do this directly ...
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erc-721 erc-20 solidity code check effects interaction pattern

Where can one locate a formally verified ERC20/ERC721 solidity code/template that adheres to security design patterns such as check effects interaction patterns?
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1answer
39 views

Use of the “indexed” keyword and token standards

Long story short, while making a blockchain crawler that would extract all ERC20 transactions I learned the hard way that ERC721 has the same "signature" as ERC20 (and probably many others that I ...
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2answers
23 views

How to trace token transfer that may contained in contract inner transactions

Take this transaction as an example. This single transaction contains 50 inner transactions. If directly calling api, what we get is a very long raw hex in input field. This input actually contains ...
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2answers
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ERC20 Token Standard Question

I've been following this wiki as a reference. The code has this snippet: // ------------------------------------------------------------------------ // Owner can transfer out any accidentally sent ...