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Questions tagged [memory]

Questions related to memory use in Solidity or by nodes

6
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1answer
4k views

TypeError: Data location must be “storage” or “memory” for parameter in function, but none was given

/// @dev Adds a new transaction to the transaction mapping, if transaction does not exist yet. /// @param destination Transaction target address. /// @param value Transaction ether value. /// @param ...
3
votes
1answer
46 views

Switching from 'storage' to 'memory' increases the gas-cost

I've read several related answers and blog posts, all of them suggesting that for the sake of reading complex state variables (i.e., arrays and structures), one should always prefer declaring the ...
1
vote
1answer
372 views

Help with setting up Private POA(Clique) Ethereum Network

Geth Version : 1.8.12-stable-37685930 Testing on Amazon EC2 t2.large(8GB RAM) machine with Ubuntu 16.04 running. I am in need of setting up a multi node private POA(Clique) ethereum network. ...
1
vote
2answers
31 views

How could Solidity 0.5.0 dynamic sized parameters be declared as storage?

As I understand it 'memory' in the EVM is a byte array and cannot be dynamically resized, whereas 'storage' is able to be resized. What is happening when a parameter is declared as storage. Where is ...
2
votes
1answer
231 views

Declaring a memory array of storage pointers in Solidity

I would like to declare a variable as a memory array of pointers to storage arrays of uint256. For example: pragma solidity ^0.4.24; contract A { uint256[] public array0; uint256[] public ...
0
votes
0answers
91 views

FATAL ERROR: Rebalance Allocation failed - process out of memory

So while running truffle compile for my contracts on AWS Ubuntu server I got the following error: <--- Last few GCs ---> [17055:0x3985730] 11958 ms: Scavenge 511.7 (553.4) -> 506.9 (553.4) ...
6
votes
2answers
2k views

How to fill dynamic in-memory array

For some reason solidity doesn't allow to push values into memory array Member "push" is not available in bytes32[] memory outside of storage. Here is sample contract code: pragma solidity ^0.4....
1
vote
1answer
668 views

Is there a maximum size for arrays in Solidity?

In my solidity code I define 3 arrays with around 700 elements inside. However, when I try to deploy the contract using Geth I am having the following error message: Error: oversized data undefined ...
3
votes
2answers
272 views

convert bytes to uint8[8] using mstore()

I know how to convert bytes to uint8[8] using mload but mstore seemed like it could be more gas efficient. Is something like this possible? function bytesToUintArray(bytes input) returns (uint8[8])) ...
1
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1answer
3k views

GPU'S Failed cannot create DAG

Last night everything is fine and then this morning I check my mining its's closed I think it was restarted or close accidentally then when I open my pool I have this error. ETH: 5 pools are ...
1
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0answers
26 views

Why is an address changing when I add it to an array?

I'm encountering a memory / storage issue (I think) w/ an array of addresses where I want to swap out one address with another. Here's how I've initialized the array: address[] public maintainers; ...
1
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1answer
1k views

Memory usage and limits for go-ethereum

geth (and swarm) seem to require a lot of memory, and there are also reports that they tend to an all you can eat approach to system limits. 1) What are the actual memory requirements for geth? 2) ...
1
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0answers
12 views

How to get live mempool transactions whitout full blokchain

I just want to analyse all mempool txs in realtime. I cant use an api because after several requests my ip gets blocked for some minutes, so I dont get the txs in this time. Thank you for help.
1
vote
2answers
50 views

Where are local variables of Primitive (Elementary) data types stored in Solidity

Though in the latest solidity compiler versions, it has been made clear that for reference variables local to a function, one needs to now explicitly mention its location modifier (memory, storage), ...
1
vote
3answers
123 views

value types(uint, bool, etc) as local variable is set to memory initially?

According to this answer, it says simpler variables like bool, uint, et cetera are not variable in length, and are therefore defaulted to memory, whereas this one mentions uint256 v; is default to ...
0
votes
1answer
32 views

Finding the memory position of mapping(address => uint) using JavaScript

I am wanting to read data from internal mappings with the following structures: mapping (uint256 => uint256) internal nums; mapping (address => uint256) internal addrToInt; Finding the memory ...
5
votes
3answers
182 views

Why memory arrays are unresizable?

I don't know the required length of my array before execution of the function.. why technically can't I resize my memory array? What is the common way to go around of this problem, if you are also ...
3
votes
1answer
71 views

Are balances of all accounts in memory or disk (storage)?

I simulated two contracts that sending balance to another and simply setting value of a variable(var a = 5;). In contrast my expectation, {var a = 5;} contract consumed more gas than the other. In my ...
0
votes
2answers
59 views

What is the proper pattern to use a temporary variable and ensure it gets stored?

A contract has a state variable, which is complex. For the example, lets say it is a mapping of structs. Inside a method, I want to access that and store the changes. Like so: contract FooManager { ...
1
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0answers
19 views

getLogs RPC makes filters?

I am stuggling with memory explosion issue of Parity on my EC2 instance. The memory usage of it keeps increasing gradually. I suspect that getLogs API call makes some garbage on the node. But I ...
20
votes
4answers
6k views

How to store IPFS hash using bytes?

Following Q/A (What datatype should I use for an IPFS address hash?) recommend us to use bytes to store IPFS hash. I was using following example(https://github.com/AdrianClv/ethereum-ipfs/blob/master/...
2
votes
1answer
76 views

memory keyword in function argument

What does the memory keyword in the argument of a function do? pragma solidity 0.4.24; pragma experimental "ABIEncoderV2"; contract Conditional { struct Condition { address to; bytes4 ...
1
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1answer
148 views

Creating a 2D in-memory array in Solidity

I'm trying to work with 2D in-memory arrays in Solidity, in which the size is not known at compile time. I've noticed that if I define the array size as a constant, then I can use this syntax, which ...
1
vote
3answers
119 views

Should I use `storage` or `memory` when just reading the value and not changing state?

pragma solidity 0.4.24; contract Test { struct Book { uint id; } Book[] books; uint public status; constructor() public { books.push(Book(10)); } ...
0
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0answers
45 views

Problem creating struct inside a struct

Currently I am developing a game in solidity, I have 2 structs as follow: struct Team{ address owner; uint[] players; uint8[] moves; } struct Game{ Team challenger; Team ...
4
votes
1answer
489 views

Assigning an array creates a pointer or copies an array? (Solidity)

Here is the code: pragma solidity^0.4.16; contract Test { struct SomeData { address[] users; } address[] nullArray; mapping(uint => SomeData) SomeDataList; function ...
0
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0answers
39 views

How to use multidimensional memory array in solidity

I'm working with a project where I have requirement of multidimensional memory array. Here is basic structure of types and person(s) Id -Types -0 -Person1 -Person2 -1 -Person1 -...
1
vote
1answer
41 views

How can I get the content of storage and memory in my private chain?

I'm looking for some methods to know the content of storage and memory while the contract is running.Mayba some useful tools or abi ? By the way, the abi of geth, debug_writeMemProfile and ...
5
votes
1answer
291 views

How does dynamic array memory reallocating work?

Let's say I have a dynamic array of some length and I want to push a new element, but memory after last elem is already used. What would happen in such case? Compiler would find a new 'chunk' of ...
4
votes
2answers
4k views

How to initialize an empty array inside a struct?

Is there a mistake in the way I initialize Bar b in the function foobar? contract Foo { struct Bar { address owner; uint[] x; } Bar[] public bars; function foobar(...
1
vote
2answers
499 views

Examples to clarify Storage vs Memory assignments / return parameters

Is there a mistake in funcB? I do not understand why/when to mention the variable name of the return parameter in the function signature. contract Foo { // State variables go to Storage uint[...
0
votes
1answer
71 views

Solidity state variable resets to default inside function

For this project, I am coding smart contracts for Ethereum using Solidity. In the following code, the variable numCertificates should initially be 1. Nonetheless, newCertificateId is 0 when assigned. ...
3
votes
2answers
124 views

How to pop from (decrease the length of) a memory array in Solidity

I have a function that gets an address array from another contract, conditionally deletes the msg.sender from the array, then saves the new array back to that contract. Because the array backerList ...
26
votes
1answer
13k views

What does the keyword “memory” do exactly?

I've been looking through the code of Etherdice and noticed that some variables are declared like ParserResult memory result; and I haven't found the keyword "memory" in any documentation. What I ...
1
vote
1answer
96 views

Compare memory pointers in Solidity

Is there a way to compare pointers in Solidity? I have two local variables: uint256[] memory a = new uint256[](256); uint256[] memory b = a; If I try a == b I get this compiler error: TypeError: ...
2
votes
1answer
199 views

Always use “memory” for variables created within functions. Bad practice?

Is it bad practice to systematically use the memory keyword for variables declared within a function (other than constructor)?
2
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1answer
2k views

The difference between contract address and wallet address

Disclaimer: this is a rather long question. To my understanding, contract address and wallet address are two profoundly different concepts, with the only thing in common being the fact that they are ...
0
votes
1answer
185 views

Why do arrays declared within functions reference storage point 0 by default?

According to the Solidity Documentation, for the following code, ". . . the compiler interprets x as a storage pointer and will make it point to the storage slot 0 by default. This has the effect ...
11
votes
2answers
1k views

error: Storage location can only be given for array or struct types

Getting the error "Storage location can only be given for array or struct types" in a setup function. The exact line is uint memory _total = 0; I'm confused by the error, because I'm not trying to ...
0
votes
1answer
72 views

how to replace an array in a mapping?

I'm learning solidity right now and making a dApp where users get paid to perform actions. Actions are paid based on certain criteria. Since I can't schedule a cron job on ethereum, I can only pay ...
1
vote
2answers
1k views

Why cryptokitties uses storage instead of memory?

There are a lot of explainations of storage and memory out there like this question or this question. But I'm wondering why cryptokitties for example uses storage instead of memory in many functions. ...
4
votes
2answers
945 views

Invalid array length, expected integer literal

I'm trying to declare an in-memory array with a fixed length: uint length = 10; uint[length] memory priorityList; However, it just displays this error message: Invalid array length, expected ...
0
votes
0answers
105 views

Solidity memory pointer

Is there any way I can use a local parameter within multiple functions? The idea is to save gas when calling functions. A parameter wouldn't have to be copied and be returned every time. Here's some ...
0
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0answers
27 views

How much storage does a smart contract use

I am trying to show the storage used by a deployed smart contract, I have a piece of code here that shows the first 10 indexes, let contractAddress = '0xf1f5896ace3a78c347eb7eab503450bc93bd0c3b' for (...
21
votes
2answers
8k views

Can I save structs in a Mapping?

Is it possible to store structs in a Mapping or any dynamic memory structure in my Solidity SmartContract?
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0answers
97 views

Quorum failure - Failed to decode message from payload

We use in our project -JP Morgan Quorum (Ethereum based) bloackchain - with istanbul voting mode. We have 4 nodes (3 of them are validators - hard coded, nonchangable) And from time to time (...
0
votes
0answers
21 views

how can I initialized bytes1 array? is there maximum size to do that?

I want to initialize bytes1 array as follows, function myData(bytes1[10] _inData) public pure { bytes1[100] memory myCData = [ bytes1(0x01), 0x02, ......so on.. till 100 ]; } But I got out of ...
1
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0answers
27 views

Solidity VM memory management

I'm trying to do an external function call in assembly. So I have to prepare a memory area that store the input args. But where's the address that I should start with mstore? I mean, there are some ...
0
votes
1answer
453 views

I got “ TypeError: Storage location can only ..”

Here is my sample contract code, but I got an error, TypeError: Storage location can only be given for array or struct types. I just wannted to define some element of a structure in a function, ...
2
votes
1answer
158 views

Can marking object as 'memory' before pushing in Array save gas?

We have a struct: struct structEx { uint num; } And an array: structEx[] arr; Have a look at this code snippet, which just instantiates the struct and push: function f() public { structEx s =...