Questions tagged [interfaces]
The interfaces tag has no usage guidance.
82
questions
0
votes
0answers
22 views
Migrate dapp from Tron to Ethereum [closed]
I have a dapp that was developed on Tron a while ago. I would like to move the dapp to the Ethereum network, so I modified and deployed the new smart contract. Now I need to modify the UI in the way ...
1
vote
0answers
15 views
ERC-2222 : Funds Distribution Token implementation for a fee contract
My MainCore contract is a contract who sell NFT, and all the sell and buy have a 1% fee for team developper (uint DevelopperCutTotalSupply).
I try to implement the ERC-2222 "Funds Distribution ...
0
votes
1answer
17 views
TxOriginVictim(msg.sender).transferTo(owner, msg.sender.balance): What is the purpose of Interface and what is TxOriginVictim(msg.sender)?
I have two contracts in the context of tx.origin Vulnerability:
pragma solidity ^0.5.8;
contract TxOriginVictim {
address owner;
constructor() public{
owner = msg.sender;
}
...
0
votes
1answer
12 views
How this snippet is linking contracts? How each contract finds the other
I'm trying to understand how can two contracts be deployed and interact with each other, given that I don't have their addresses before deployment. I ended in this question and I don't understand the ...
0
votes
1answer
24 views
Why use the Interface (IERC20), instead of the implementation contract (ERC20)?
I'm playing with a contract that uses an ERC20 token, and I can see basically 2 options to init the token:
Use the interface contract (IERC20)
Use the implemented contract (ERC20)
Interface version:
...
0
votes
1answer
54 views
Reflect Base contract's update in another contract
I have wanted to know what concept is it called when we want two contracts which are deployed on the Network, reflect the transaction and updates in another contract.
for example:
contract Base{
...
1
vote
3answers
48 views
Do view functions cause reentrancy vulnerabulity?
It's well known that calling an external function before changing something in the contract causes a security problem called "reentrancy vulnerability".
Does calling an external function ...
0
votes
0answers
16 views
How to use web3 when one smart contract is interfacing with another?
A few months back I posted this question on this form. Since then, I've used the interface method to make my smart contracts interact together. I didn't have any problem while testing and developing ...
0
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0answers
27 views
how to pass fix size array via interface in solidity 0.4.25
I used the following code
interface test{
function testfunction(uint[20] memory P, uint[20] memory Q) external returns(uint,bool,uint);
}
It gives the error Location has to be calldata for external ...
1
vote
1answer
19 views
In interface does the function listed have to be exactly the same as they are in contract?
In solidity 0.7.x, I am creating an interface of contract A in contract B to allow contract B call functions in contract A.
contract A {
function transfer(address recipient, uint256 amount) public ...
0
votes
2answers
41 views
remote contract function call with solidity
I've deployed this very simple Contract:
contract Contract1
{
function myfunction(uint param1) public returns (uint)
{
return param1+1;
}
}
Now, I've deployed a second contract:
...
0
votes
1answer
43 views
Is it possible to call a public array from another contract?
Let's say there is a uint[] public MyArray declared in contract_A.
Is there a possiblility to create an interface contract_A that would allow to read the values in MyArray from another contract, or ...
2
votes
2answers
258 views
Can't override ERC20 Methods
I try to override ERC20 methods ... The doc says it should be possible but I get the error:
CompileError: @openzeppelin/contracts/token/ERC20/ERC20.sol:96:5: TypeError: Trying to override non-virtual ...
0
votes
1answer
91 views
ERC20 Interface
When you make a token, must you have an ERC20 Interface (such as the one below)? What is the purpose of it?
pragma solidity 0.6.6;
/// @notice ERC20 https://eips.ethereum.org/EIPS/eip-20 with ...
0
votes
0answers
95 views
Wrapping functions in interfaces to enable higher order function capability in Solidity?
Let's say I want to have higher order function capabilities in my Solidity Dapp. Also I want to be able to pass in new functions as input to higher order functions contained within contracts that were ...
0
votes
1answer
96 views
Uncaught TypeError: TheContract.at is not a function
just trying my first steps in ethereum and web3. So i found this tutorial:
https://www.youtube.com/watch?v=hcTPjpPvas8
But it raise an error:
index.html:85 Uncaught TypeError: TheContract.at is not a ...
0
votes
1answer
368 views
How to call “payable function” via interface in solidity [duplicate]
I have a function marked as payable in contract A and I want to call it from contract B so that msg.value in contract A can have its desired value and contract A must have balance of sent amount , how ...
2
votes
1answer
207 views
How to properly define an interface in Solidity 0.6?
One of the breaking changes of solidity 0.5 was making explicit function visibility mandatory, hence all interface functions must be defined as external today.
In solidity 0.6, there seems to be two ...
1
vote
1answer
42 views
How to deploy smart contract so that average user can interact with its public functions?
I sucesfully wrote and deployed smart contract using Remix and Metask to generate hashes used as keys. This contract has few payable public functions that set or get some numbers. After deploying ...
0
votes
1answer
34 views
Like an ERC20 interface, do we have any interface or a smart contract that supports creating and transferring Ether on Ethereum?
To create a token on Ethereum, we use ERC20 token interface to design our token smart contract that captures functions required like mint(), tranfer(), balanceOf(), etc.
Similarly, do we have any ...
0
votes
1answer
117 views
Buy tokens form other smart contract using interface
I have two separate contracts, let's say Token and BuyFrom.
pragma solidity >=0.4.22 <0.7.0;
interface InterfaceToken {
function invest(address contributor) external payable;
}
contract ...
0
votes
0answers
35 views
is there any possibility to read struct via interface from deployed contract?
the contract is deployed which has no view function for that particular struct, is there any way to read values via interface in another contract which I want to write and deploy ?
0
votes
1answer
117 views
What is the use of a interface or function without implementation?
Take, for example, this code.
The interface contains function without implementation, so how it's useful.
pragma solidity ^0.5.0;
interface Calculator {
function getResult() external view returns(...
0
votes
2answers
46 views
What does it mean to declare an item of type contract?
Wasn't quite sure how to word the title, but in the following code:
contract KittyInterface {
...
}
contract ZombieFeeding is ZombieFactory {
KittyInterface kittyContract;
}
what is the ...
0
votes
2answers
55 views
How bad is it to change a function inside ERC721 interface?
I'm creating a NFT and I want the transferFrom function to be payable. In order to do so I need to edit the ERC721 interface and make that function payable also there.
If I do so everything compiles ...
1
vote
1answer
58 views
What does mutability guarantees mean in erc721
Some functions from ERC-721 interface contain payable modifiers.
function transferFrom(address _from, address _to, uint256 _tokenId) external payable;
I was wondering why it is payable and found ...
2
votes
0answers
39 views
Nested usage of interfaces?
Using solidity ^4.x, it seems I can use an interface as a parameter type in a function from a different interface.
Example:
interface IERC20 {
function transfer() external;
}
import "./IERC20....
0
votes
2answers
4k views
File import callback not supported import “./IERC20.sol”;
when I try to compile my contract I see errors like this :
DemirelToken.sol
https://eksiup.com/p/4z49413damc3
here's the code :
pragma solidity ^0.5.0;
import "node_modules/openzeppelin-...
3
votes
1answer
451 views
ERC721: Interface ID Registration
Why we need to register Interface ID in ERC721 token. I was just going through the openzeppelin-solidity erc721 code and curious to know that why we need to use this. That interface id register code ...
3
votes
1answer
1k views
How to interact with ERC20 interface?
My target is to send from the ERC20Wrapper.sol deployed contract BAT tokens to my hard coded address.
I've created ERC20 Interface:
pragma solidity 0.4.18;
interface ERC20 {
function ...
0
votes
1answer
55 views
DAPP WALLET transaction always fails
To improve my skills in solidity I'm working on a "wallet dapp". Based on smart contracts only, users can send ERC20 to another wallet. It works like that:
user gives the following parameters: ...
0
votes
1answer
402 views
Solidity, how to cast SmartContract type to address
I am currently a bit stuck with my contract, the issue is following:
I define a smartcontract type which is used for another address (aka address is smartcontract that provides the specified interface)...
0
votes
3answers
224 views
REMIX:This contract does not implement all functions and thus cannot be created
What should I do?
pragma solidity ^0.4.21;
contract ScoreInterface {
function hit() public;
function score() public view returns (uint);
}
This contract does not implement all ...
0
votes
2answers
316 views
Solidity how to check if user is already used another contract?
I am trying to figure out how to set up a simple communication between contracts.
For example, we have a contract Passport, in which the user writes his data. After that, through the Election ...
1
vote
1answer
23 views
In case we have an interface written in a seperate .sol file how do we migrate it successfully?
HI consider i have 3 smart contracts A,B,C.
I have a separate file D.sol which is an interface used in all A,B and C.
What would the migration script look like for this project?
2
votes
0answers
234 views
Can I extend the interface of a contract without redeploying it?
The case I'm dealing with is a contract which should serve as a Data Abstraction Layer.
So ideally, it should provide only getter functions and setter functions.
For example, my interface is:
...
0
votes
1answer
113 views
how to parse values returned by one contract into another?
I've two contracts deployed one is UserRegistration and another is Exam
I've getUser(uint id) method to fetch data of particular user using users mapping,
function getUser(uint _id) public constant ...
1
vote
1answer
187 views
Can abstract contracts in solidity have state variables?
I want to have one deployed contract with my data structure and all data and another separate contract with functions that calls the deployed contract. If i've understood things correctly, one should ...
0
votes
1answer
196 views
Enum in interfaces
Following the documentation I try to add a enum to my interface. Inside the interface I have a method called get that returns one of the enum value. Im trying to add the enum to the interface, because ...
0
votes
1answer
113 views
Interfaces implementation visibility
I have this interface:
pragma solidity ^0.4.24;
interface EventsInterface
{
function removeValueFromArray(uint _userId, uint[] array) external
returns(uint[]);
}
And this contract:
pragma ...
0
votes
1answer
141 views
Interface overriding
I have two contracts. One of them inherits another. Inside the parent contract I have the interface
interface Token {
function transfer(address to, uint256 value) external returns (bool);
}
I ...
0
votes
1answer
2k views
Interfaces in solidity
I have one interface like the following:
pragma solidity ^0.4.11;
interface TokenInterface {
function transfer(address recipient, uint amount) external returns(bool);
}
And the implementation in ...
2
votes
2answers
496 views
Variables in interfaces
Im trying to implement my first interface. But when I try to add a new variable, Remix tell me that can´t add variables in interfaces.
It have sense to set the fixed variables that the extended ...
1
vote
1answer
47 views
Simple but important question: How to get the value of contract's state when using Metamask? [closed]
I'm designing an HTML file (or a user interface: UI) for my smart contract.
let's assume that my contract has a state as follows:
address public owner;// it is set to "...
0
votes
0answers
77 views
Why is not Metamask invoked in my user interface?
I'm running a private Ethereum blockchain on my computer.
I've installed Metamask on my chrome as well.
I can create an account on metamask, and then interact with my smart contract deployed on my ...
0
votes
1answer
87 views
Error in external function parameter defination for an interface
Dear community members,
I have come across an error while defining an interface (just using the standard one interface ERC721TokenReceiver)
this interface is mentioned in this link https://github....
1
vote
2answers
40 views
Is it possible to have an optional property or method in an interface?
I currently can't deploy any contract which doesn't adhere 100% to the specified interface(s). Is there a way to mark some properties or methods as optional and, if not, is this a planned feature?
1
vote
2answers
216 views
Why are all parameters prepended by an underscore in ERC interfaces? [duplicate]
For instance, both ERC-721 and ERC-725 have underscores(_) before any function parameter.
I understand that normally their goal is to avoid variable overloading. However, what is the rationale for ...
0
votes
1answer
73 views
Contract Using An Interface Is Not Compiling
I am learning Solidity and I am using Remix to experiment and enhance my learning. I am currently trying to create a simple contract that uses an Interface.
pragma solidity ^0.4.19;
contract ...
2
votes
2answers
960 views
How to create Interface to read Struct in mapping?
There are 2 contracts A and B.
A has a mapping which returns Struct:
mapping (bytes32 => Cup) public cups;
How can we read the cups mapping in contract B?
Following code doesn't work for sure:...
