Linked Questions

4 votes
1 answer
7k views

Listening to Events from another smart contract [duplicate]

I want to listen to an event from inside another (deployed) smart contract. I am a complete noob to Ethereum and Solidity. So please excuse me for stupid questions, I might have misunderstood ...
Sajjon's user avatar
  • 141
3 votes
1 answer
1k views

How read events from solidity [duplicate]

I made a solidity contract but I want to get the event in another contract, is it possible to watch the event in that way?
Louis's user avatar
  • 1,155
1 vote
1 answer
2k views

How to watch events on smart contract? [duplicate]

All the existing questions explains to catch the event on client end or server. How to catch the event on smart contract itself? Here's what I'm looking for: Contract A emits the event Contract B ...
Sowmay Jain's user avatar
0 votes
1 answer
1k views

Listen to a solidity event from a smart contract function [duplicate]

I have the following event: event WaitingPlayer2(address indexed player2); Which I call through: function partecipateAsPlayer2(address player2) public{ emit WaitingPlayer2(player2); } Is ...
iLikeKFC's user avatar
68 votes
5 answers
58k views

What is the cost to store 1KB, 10KB, 100KB worth of data into the ethereum blockchain?

Whatever is stored in the blockchain is immutable which means I can fetch this data back in the future. As of today (2016-feb), How does one store a 1kb, 10kb, or 100kb or arbitary data/text in the ...
Patoshi パトシ's user avatar
36 votes
5 answers
33k views

How to access the event log by knowing the contract address (web3)?

How can I access a log stored in one of the tx of the contract via web3? Code example: event newtest(string indexed name, uint indexed idlevel,string indexed multib, string objmulti, uint objnm); ...
b1818762's user avatar
  • 363
28 votes
2 answers
3k views

Is it a good practice to log an event every time I throw in Solidity?

In Solidity (0.3.2) I am aware that there is no way to throw specific exceptions. (Everything is an invalid JUMP error.) It seems beneficial to have a way to log specific errors. Does it make sense to ...
Raine Revere's user avatar
  • 3,610
27 votes
1 answer
4k views

Are events permanently stored and reliably available to contracts in the future?

I've seen this forum post about using Ethereum as an event store: Events in Solidity, using blockchain as eventstore. However, it doesn't seem conclusive. For instance it says: I confirmed with ...
Noah Thorp's user avatar
7 votes
1 answer
2k views

What's cheaper — contract storage | log data | transaction input?

I want to collect user data and store it on the blockchain. Let's say I need to store usernames. Is the cost of storing 1 byte on the blockchain different for contract storage/log data/transaction ...
manidos's user avatar
  • 4,298
7 votes
1 answer
837 views

What are the benefits of using events over dedicated indexed variable?

Good day. I'm trying to grasp the concept of events in the EVM and I just can't understand what is the incentive of using events. Why not just use a dedicated public index that will hold information? ...
shultz's user avatar
  • 1,091
2 votes
1 answer
603 views

Will it be possible to get a contract's balance by block number in Solidity?

Will it be possible to get address state at a given block within smart contract execution logic? Something like: block(10297202).(address('Ox...').balance) I assume it's not possible currently due to: ...
user3652172's user avatar
1 vote
3 answers
609 views

Is it possible for smart contract to link received tokens to the senders

I know when my smart contract has a payable fallback function, I can record who have sent ether to the contract and how much ether each of them have sent by storing the msg.sender and msg.value data ...
hellopeach's user avatar
0 votes
0 answers
916 views

Can I subscribe to events emitted by another contract?

I am trying to subscribe to an event emitted by an existing library's smart contract. I've found examples of how to subscribe to events emitted by my contract using web sockets and my contract ABI as ...
jason's user avatar
  • 1
2 votes
1 answer
259 views

Can a contract that receives a token know the origin of the tokens?

Can a contract that receives a token know the origin of the tokens? (Assuming the token follows the token standard.)
Fernando Tiberti's user avatar