Like solidity supports ETH, TRON VM supports trx and sun, 1 trx = 1000000 sun, case sensitive, only support lower case. Tron-IDE supports trx and sun, remix does not support trx and sun. We recommend to use Tron-IDE instead of remix to build TRON smart contract.
block.blockhash (uint blockNumber) returns (bytes32): specified block hash, can only apply to the latest 256 blocks and current block excluded
block.coinbase (address): SuperNode address that produced the current block
block.difficulty (uint): current block difficulty, not recommended, set 0
block.gaslimit (uint): current block gas limit, not supported, set 0
block.number (uint): current block number
block.timestamp (uint): current block timestamp
gasleft() returns (uint256): remaining gas
msg.data (bytes): complete call data
msg.gas (uint): remaining gas - since 0.4.21, not recommended, replaced by gesleft()
msg.sender (address): message sender (current call)
msg.sig (bytes4): first 4 bytes of call data (function identifier)
msg.value (uint): the amount of SUN send with message
now (uint): current block timestamp (block.timestamp)
tx.gasprice (uint): the gas price of transaction, not recommended, set 0
tx.origin (address): transaction initiator Each command of smart contract consume system resource while running, we use 'Energy' as the unit of the consumption of the resource.