Global Variables

These are special variables which exist in global workspace and provide information about the blockchain and transaction properties.

Description :

• 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 payable)  -  Sender of the message (current caller)
• msg.sig (bytes4)  -  First four bytes of the calldata (function identifier)
• msg.value (uint)  -  Number of wei sent with the message
• tx.gasprice (uint)    Gas price of the transaction
• tx.origin (address payable)    Sender of the transaction

Code Example : 

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract g_variables {
  
   function block_info() public view returns(address payable, uint, uint, uint, uint){
      return (block.coinbase, block.difficulty, block.gaslimit, block.number, block.timestamp);
   }

   function msg_info() public payable returns(bytes calldata, address, bytes4, uint){
      return (msg.data, msg.sender, msg.sig, msg.value);
   }

   function tx_info() public view returns(uint, address, uint256){
      return (tx.gasprice, tx.origin, gasleft());
   }

}