Linked Questions

Who can tell me what is the difference between revert,assert,require,throw!

Simple and appropriate data organization can challenge Solidity newcomers. It wants us to organize everything in ways many of us aren’t accustomed to. Are there well-solved general patterns for ...

Im learning Solidity. As far as I'm aware, it's recommended using "require" to handle errors. But, I'd like to inform the users about the kind of errors they make, e.g. an argument is invalid or out ...

When you throw an exception, all gas is consumed. What is the rationale for this design decision?

Pre Byzantium fork, I could use gas == gasUsed to detect when a transaction has failed (further details in How can the transaction status from a thrown error be detected when gas can be exactly the ...

I have a mapping where the key is the artist name, the value is msg.sender address. In a function, I want to check if the parameter username has already existed in the mapping keys, if yes, i will ...

According to the docs revert() will not consume any gas: Note that assert-style exceptions consume all gas available to the call, while revert-style exceptions will not consume any gas starting ...

In the Tron contract (a large ICO listed on many exchanges) lies this modifier which is used for all token transfers : modifier validAddress { assert(0x0 != msg.sender); _; } I understand ...

I am currently taking a look at the slides from this presentation I suppose the question is less with formal verification and more with solidity. Can some one help me understand what can possibly go ...

In case people send ERC20 tokens to my contract, I want to be able to retrieve them. Hence the following function: /** * @dev Allows owner to transfer ERC20 tokens to vault * @param _token the ...

Since assert would consume all gas and require would return all gas, Is there any reason to use assert not require? Use require to refund gas seems always a better choice than consuming them? I saw ...

As is well documented, require is preferred over assert for error conditions, eg. Difference between require and assert and the difference between revert and throw Solidity might someday include the ...

Solidity v0.4.10 introduced the revert() and require() functions, along with support for the REVERT opcode. As far as I can tell, this means that any contract compiled using ^0.4.10 will express ...

I've just downloaded Mist 0.9.0 and I tried to compile a new contract but it does not let me do it with this error: "throw" is deprecated in favour of "revert()", "require()" and "assert()". ...

I'm having trouble getting the array of "watchers" to persist after I: Deploy the contract Create Magic with name "test1" Execute watchMagic (with test1's magic id) Execute watchMagic (with test1's ...