Sending Ether (transfer, send, call) in Blockchain / Solidity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the transfer function do when sending Ether in Solidity?

The transfer function sends a fixed amount of Ether to an address and throws an error if the transfer fails, reverting the transaction.

beginner

How does send differ from transfer when sending Ether?

send sends Ether but returns a boolean indicating success or failure instead of throwing an error. It requires manual error handling.

intermediate

What is the main advantage of using call to send Ether?

call is more flexible and forwards all available gas, allowing interaction with contracts that require more gas. It also returns success status and data.

advanced

Why should you be careful when using call to send Ether?

Because call forwards all gas by default, it can lead to reentrancy attacks if not handled properly. Always use checks-effects-interactions pattern.

beginner

What happens if transfer or send fails to send Ether?

transfer throws an error and reverts the transaction, while send returns false and requires manual error handling.

Which function automatically reverts the transaction if sending Ether fails?

A transfer

B send

C call

D approve

transfer throws an error and reverts the transaction on failure.

Which function returns a boolean indicating success or failure when sending Ether?

A send

B transfer

C call

D mint

send returns true or false depending on success.

Which method is recommended for sending Ether when you need to forward all gas and handle complex interactions?

A transfer

B send

C delegatecall

D call

call forwards all gas and allows complex interactions.

What is a major security risk when using call to send Ether?

A Gas limit exceeded

B Reentrancy attack

C Integer overflow

D Stack overflow

Using call can open the door to reentrancy attacks if not handled carefully.

If you want to send Ether and handle failure manually without reverting, which function should you use?

A call

B transfer

C send

D selfdestruct

send returns false on failure, allowing manual handling.

Explain the differences between transfer, send, and call when sending Ether in Solidity.

Think about error handling and gas forwarding.

Describe a safe pattern to send Ether using call to avoid security risks.

Focus on security best practices.