Blockchain

Topics Covered

• Solidity

• Block 101

• Custom ERC20

• Contract

Working on a block

Block and Transaction Properties

• blockhash(uint blockNumber) returns (bytes32): hash of the given block - only works for 256 most recent, excluding current, blocks

• block.chainid (uint): current chain id

• block.coinbase (address payable): current block miner’s address

• block.difficulty (uint): current block difficulty

• block.gaslimit (uint): current block gaslimit

• block.number (uint): current block number

• block.timestamp (uint): current block timestamp as seconds since unix epoch

• gasleft() returns (uint256): remaining gas

• msg.data (bytes calldata): complete calldata

• msg.sender (address): sender of the message (current call)

• msg.sig (bytes4): first four bytes of the calldata (i.e. function identifier)

• msg.value (uint): number of wei sent with the message

• tx.gasprice (uint): gas price of the transaction

• tx.origin (address): sender of the transaction (full call chain)