Units and Globally Available Variables
This section explains how Solidity's standard Ether/Time units and global execution variables (block, tx, msg) map to NeoVM semantics.
For a split reader guide focused on execution globals, see Execution Context.
Ether Units
A literal number can take a suffix of wei, gwei or ether to specify a subdenomination of Ether, where Ether numbers without a postfix are assumed to be Wei.
WARNING
Neo GAS Difference: Ether unit literals (1 ether = 10^18 wei) are parsed for source compatibility but emit a warning. Neo GAS uses 10^8 decimals, not 10^18. You should adjust your constants to match Neo GAS units:
// ⚠️ EVM units — warning emitted
uint256 fee = 0.1 ether; // 10^17 wei — wrong for Neo
// ✅ Neo GAS units
uint256 fee = 10_000_000; // 0.1 GAS (10^7, since GAS has 10^8 decimals)Time Units
Suffixes like seconds, minutes, hours, days and weeks after literal numbers can be used to specify units of time where seconds are the base unit. These map perfectly to NeoVM logic.
Block and Transaction Properties
The neo-devpack-solidity compiler auto-maps EVM globals to approximate Neo equivalents. Auto-mapped features compile successfully but emit a compiler warning when the semantic match is not exact.
| Solidity / EVM | NeoVM / Neo N3 | Notes |
|---|---|---|
block.timestamp | System.Runtime.GetTime | Returns block time in milliseconds, normalized to seconds by the compiler. |
block.number | Ledger.currentIndex | Returns the current block height. |
block.chainid | Neo network magic | Compile-time constant. Mainnet: 860833102, Testnet: 894710606. |
block.coinbase | address(0) | Auto-mapped with warning. dBFT consensus has no block miner. |
block.difficulty / block.prevrandao | Runtime.getRandom() | Auto-mapped with warning. Different randomness model. |
block.gaslimit | Policy.getExecFeeFactor() | Auto-mapped with warning. Different gas accounting model. |
block.basefee | Policy.getFeePerByte() | Auto-mapped with warning. Different fee model. |
blockhash(n) | Ledger.getBlockHash(n) | Auto-mapped with warning. Returns Neo block hash. |
block.sha3 | Ledger.currentHash | Auto-mapped with warning. Deprecated in Solidity 0.8+. |
tx.origin | First signer script hash | Maps to the first transaction signer. Warning: authorization anti-pattern. |
tx.gasprice | Policy.getFeePerByte() | Auto-mapped with warning. Different fee model. |
Message Properties
| Solidity / EVM | NeoVM / Neo N3 | Notes |
|---|---|---|
msg.sender | System.Runtime.GetCallingScriptHash | Returns the script hash of the calling contract or transaction signer. |
msg.value | onNEP17Payment amount parameter | Only valid inside NEP-17/NEP-11 payment callbacks. No equivalent outside that context. |
msg.data | — | Approximated as selector || abi.encode(current args) outside onNEP17Payment. |
msg.sig | — | Approximated as the current function selector (with warning). Internal-call semantics still differ from EVM. |
Contract Context
| Solidity / EVM | NeoVM / Neo N3 | Notes |
|---|---|---|
this | System.Runtime.GetExecutingScriptHash | Returns the script hash of the current contract. |
gasleft() | System.Runtime.GasLeft | Returns remaining GAS for the current invocation. |
selfdestruct(addr) | ContractManagement.destroy() | Auto-mapped with warning. No refund. Permanent and irreversible. |
address.codehash | Contract script hash | Auto-mapped with warning. Non-contract addresses return bytes32(0). |
address.code | Contract script bytes | Auto-mapped with warning through ContractManagement.getContract(). Non-contracts return empty bytes. |