Linked Questions

81 votes
13 answers

How to get contract internal transactions

I'd like to get the contract internal transactions like: I'm using web3 API. Is there any way to do it? Where do ...
Paul Exchange's user avatar
75 votes
7 answers

How do you get a json file (ABI) from a known contract address?

I want to watch a Solidity contract using the Mist browser. I know how to do that and it needs the address and the json. I have the address, but I don't have the json. I do have the source code. Can ...
Thomas Jay Rush's user avatar
64 votes
7 answers

How can I verify that a contract on the blockchain matches the source code?

Given the (Solidity) source code of a smart contract, is there a way to deterministically compile the code and compare it with the code on the blockchain? I want to verify that the contract does what ...
J-B's user avatar
  • 8,961
57 votes
4 answers

How to call a contract method using the eth_call JSON-RPC API

Ok, so I'm trying to call a contract method using the methods provided by the Ethereum JSON RPC interface. The JSON RPC is running on an Ubuntu machine. Unfortunately, I can't really get a result back ...
MethDamon's user avatar
  • 803
54 votes
8 answers

How to quickly test a Solidity function?

There are snippets and functions of Solidity code provided on this Ethereum Stack Exchange and other sites. What are ways to quickly test them, possibly debug a little, and play around?
eth's user avatar
  • 86k
32 votes
3 answers

What is calldata?

What is calldata? I learned that there are three types of memories: Storage Memory Stack In the Ethereum docs, it says that the function parameters are of type memory by default. However, I've also ...
Sheikh's user avatar
  • 455
25 votes
5 answers

Pass a function as a parameter in Solidity

Can you pass a function as a parameter in Solidity? My guess: There is the concept of address in Solidity, but they represent contracts. Contracts can have fallback functions, but I don't think you ...
Karl Floersch's user avatar
25 votes
2 answers

Do I need a compiled contract just to get the ABI definition?

Why do I need a compiled version of the contract just to get the ABI definition? Seems like the contract address should be enough. Im very confused because I am simply trying to run a contract ...
ZMitton's user avatar
  • 2,770
18 votes
1 answer

What does Solidity's "call" function mean?

address nameReg = 0x72ba7d8e73fe8eb666ea66babc8116a41bfb10e2;"register", "MyName"); //1"fun(uint256)")), a); //2 if(!{throw;} //3 Here ...
Jim Green's user avatar
  • 687
16 votes
9 answers

Is there a way to extract ABI from a deployed contract?

I am building a web UI for testing smart contracts and currently I have to supply the ABI for a contract I test. Is there a way to extract the ABI from a deployed contract (preferably programmatically)...
Andrey's user avatar
  • 1,147
13 votes
2 answers

Why does an empty message still invoke the code of the contract?

An empty message still invokes the code of the contract and is the mechanism that allows Solidity to implement a feature of a fallback function per contract. But when is empty, why does ...
eth's user avatar
  • 86k
12 votes
3 answers

How does the EVM find the entry of a called function?

I read the source code of go-ethereum and confused about how does the EVM find the entry of a called function. As the specification said, the data field in a transaction specifies the function and the ...
rong jialei's user avatar
12 votes
2 answers

Clarification of "256 bit word" semantics

EVM has "256bit words". Some cases treat strings shorter than 32 bytes (256 bits) as left-justified ascii (packed into the most significant bytes of the word). Does this mean that the word value of ...
rethsid's user avatar
  • 1,898
11 votes
2 answers

What is a function signature and function selector in solidity (and EVM languages)?

I've heard the term "function signature" as well as "function selector", what are they? What are they for?
Patrick Collins's user avatar
9 votes
2 answers

Is sending some datas in the data field safe?

An airdrop ask to send it 0ETH with 150000 GAS and some datas in DATA field. Is it safe? What could be the aim of this transaction? Thanks.
Pat Hibulaire's user avatar

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