65
votes
Accepted
What does the keyword `super` in Solidity do?
The super keyword in Solidity gives access to the immediate parent contract from which the current contract is derived. When having a contract A with a function f() that derives from B which also has ...
- 8,784
4
votes
Accepted
What is an Internal function type variable?
Internal functions which accept function type as an argument can take internal, public and private functions when called. For example:
library L {
function ops(
uint256 _a,
uint256 ...
- 106
3
votes
Accepted
If not in the EVM, where do internal functions execute?
internal functions are called through a JUMP / JUMPI instruction, simply jumping to another point of the current code. This makes sense because internal functions do not change context (i.e., they ...
- 7,901
3
votes
Accepted
Is it possible to use interface functions as types?
I asked the same question in the Solidity Matrix server, and a Solidity language developer has replied by saying that this is not currently possible.
The reason being that there's no runtime type ...
- 18.7k
3
votes
Where in the code of this unstake function is ETH actually transferred?
The BridgeRouterFacet contract's unstakeETH() function:
function unstakeEth(address bridge, uint88 zethAmount)
external
nonReentrant
onlyValidBridge(bridge)
{
if (...
- 1,745
3
votes
Accepted
What is the correlation between "Hash" (Method ID) & "Name"
This is not a Method ID (not a hash of a function name that'd be in the deployed contract) even though Etherscan shows it as Method in the UI.
And that it shows as rugPullAll and even other ones if ...
- 1,178
3
votes
Calling private functions using Yul ( Solidity )
tl;dr, to answer your question:
Is there any way at all to call private functions using inline
assembly?
Yes, it is possible, but not with the call() instruction.
Long answer + extras:
If you're ...
- 672
2
votes
DAO like functionality on Gnosis?
The Zodiac team from Gnosis is building DAO tools around the Safe. There are quite some extensions already and the community is open for new proposals.
You can find more information on the Zodiac ...
- 5,144
2
votes
Solidity: Restrict access to functions
Yes, the modifiers will work even if the function is called inside another function.
I have tested it in Remix and the function seems to work as intended, and only the owner can use it.
- 1,014
2
votes
Accepted
Does a double space have an effect inside function declaration?
They are both the same.
this can easily be tested in Remix by creating a contract with both methods and it will tell you that they conflict as they are parsed as the same.
Even when you look at the ...
- 5,144
2
votes
Accepted
Private variables with public view functions
The pattern you noticed is competing with the approach of using an internal storage variable.
The general idea here is you can read the variables and not write. It allows the contract to make some ...
- 4,730
2
votes
Accepted
Why and when to user require(bool) on functions
You could, but it would not be safe because call() won't revert if the external contract execution does. It's highly discouraged and generally unsafe.
- 635
2
votes
Accepted
Can solidity function have optional parameter?
It's not about Solidity, but how ethersjs abstracts the call to the contract and does some encoding and creates the transaction for you.
Basically, from a js contract instance created with ethersjs, ...
- 4,649
2
votes
modifier vs function which method is more efficient in terms of gas?
It would depend on the code, but there wouldn't generally be much in it in terms of execution, but could be a significant different in the size of the deployed code. When the code is deployed the ...
- 1,248
2
votes
Accepted
modifier vs function which method is more efficient in terms of gas?
I've tested in Remix, although both function calls reverted, both methods had approximately similar execution cost (Cost only applies when called by a contract), with toDoSomething1() 23410 gas vs. ...
- 4,308
2
votes
Accepted
Where are Function stored in EVM?
Basically, given a function selector, your bytecode knows where the functions are kept and use the selector to know where to jump your code to.
Here is a useful link:
https://blog.openzeppelin.com/...
- 2,000
2
votes
Normal function asking to be made Payable
It's because the 'person' creation is wrong so the tx reverts.
Here is the proper way:
pragma solidity 0.8.16 ;
contract arr
{
uint i = 0 ;
people[] public person ;
struct people
...
- 2,000
2
votes
Does it make any sense to specify reference type function input parameters as calldata if the given function is only called contract to contract?
I am wondering however what is the point of specifying the input argument in a function as calldata, if you know that it will only be called from a contract (hence no gas savings of using the real ...
- 7,901
2
votes
Accepted
The redundant `_from` parameter in the `transferFrom` function of an ERC721
Great observation on the _from parameter! I never noticed this before.
Here are the two key reasons for its inclusion in the transferFrom() function in ERC-721:
As you know, ERC-721 is strongly ...
- 2,441
2
votes
Accepted
SOLIDITY NOOB QUESTION. Is it necessary to specify that a function is a view function if it's obviously a view function?
It's not strictly necessary to specify that a function is a view function if it's already obvious from the function's code that it only reads data from the blockchain and doesn't modify it. However, ...
2
votes
Accepted
ParserError in solidity
Your code is missing the last curly bracket, which is the closing bracket for the contract
Here is the updated code try this. No major changes just added a bracket at the end.
// SPDX-License-...
- 5,320
2
votes
Accepted
How do you use `delete` on a function?
You cannot delete a function. What you can delete, though, is a variable that points to a function.
The documentation, likely, meant to say "The same happens if you call a function after using ...
- 30.3k
2
votes
How to use another deployed smart contract functions?
That depends on how you want the functions to be executed. If you wish to execute them in the context of your own contract, you should look into proxies => https://docs.openzeppelin.com/upgrades-...
- 1,257
2
votes
Invoking a function with different amount of input than the function takes
Assuming this sub function is copied from OpenZeppelin's SafeMath.sol library, or similar.
In Solidity, you can declare special library functions by declaring functions inside a library (instead of a ...
- 607
2
votes
Two people calling this function at exactly the same time
Even if two transactions are created at virtually the same exact time, there will be a definite order decided upon by the miner/validator of the block where the transactions took place.
This means ...
- 1,745
2
votes
Accepted
Possible way to hack Solidity into executing a function directly from a struct as a method? (v0.8.20)
It's a perfectly legitimate use. Only there are some restrictions: the called function must be executed within the context of the same contract. You can read the official documentation: https://docs....
- 1,017
2
votes
Calling private functions using Yul ( Solidity )
When compiling internal and private functions, selectors are not created on them. This means that they cannot be called by passing the address of the function selector. Theoretically, you could find ...
- 1,017
2
votes
Calling private functions using Yul ( Solidity )
This is not possible.
As Alexey said, a function selector is not created for private variables. Whenever someone calls a solidity smart contract, the first thing that contract does is figure out where ...
- 12.4k
1
vote
Accepted
If the smart contract does not include the withdrawal function, will that ether be stored in the smart contract for life?
If the smart contract does not include the ability to send ether to other people, will that ether be stored in the smart contract for life?
Yes.
Another way to withdraw is to add functionality for ...
- 22.5k
1
vote
Accepted
Function cannot be declared as view because this expression (potentially) modifies the state
There are a few different perspectives into this. Let's see.
Blockchain's perspective
The blockchain basically just stores data. Data can be read from any node. State changes aren't free, reading data ...
- 30.2k
Only top scored, non community-wiki answers of a minimum length are eligible