TRC-20 protocol interface

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Prerequisites

TRC-20

TRC-20 contract standard

TRC-20 is a set of contract standards for issuing fungible token assets on TRON. Any contract that implements the required functions and events below is considered a TRC-20 contract. Wallets and exchanges integrating a TRC-20 contract use this standard set of functions and events to interact with the contract.

Required interface

Every TRC-20 contract must implement the functions and events below:

interface TRC20 {
    function totalSupply() external view returns (uint theTotalSupply);
    function balanceOf(address _owner) external view returns (uint balance);
    function transfer(address _to, uint _value) external returns (bool success);
    function transferFrom(address _from, address _to, uint _value) external returns (bool success);
    function approve(address _spender, uint _value) external returns (bool success);
    function allowance(address _owner, address _spender) external view returns (uint remaining);

    event Transfer(address indexed _from, address indexed _to, uint _value);
    event Approval(address indexed _owner, address indexed _spender, uint _value);
}

Function reference

Function	Purpose
`totalSupply()`	Returns the total supply of the token.
`balanceOf(address _owner)`	Returns the token balance of `_owner`.
`transfer(address _to, uint _value)`	Transfers `_value` tokens from the caller's account to `_to`.
`approve(address _spender, uint _value)`	Authorizes `_spender` (often a DApp contract) to transfer up to `_value` tokens from the caller's account.
`transferFrom(address _from, address _to, uint _value)`	Allows an approved spender to transfer `_value` tokens from `_from` to `_to`. The owner account must have called `approve` first.
`allowance(address _owner, address _spender)`	Returns the remaining number of tokens `_spender` is still allowed to transfer from `_owner`.

Event reference

Event	Fires when
`Transfer(_from, _to, _value)`	A successful `transfer` or `transferFrom` moves tokens. Also fires on mint (`_from = 0x0`) and burn (`_to = 0x0`).
`Approval(_owner, _spender, _value)`	A successful `approve` sets a new allowance for `_spender` on behalf of `_owner`.

Optional metadata

The following public state variables are optional but supported by virtually every wallet and explorer:

string public name = "TRONTestCoin";
string public symbol = "TTC";
uint8 public decimals = 6;

Field	Purpose
`name`	Human-readable name of the token.
`symbol`	Short abbreviation displayed by wallets and exchanges.
`decimals`	Number of decimal places used in token amounts. `decimals = 6` means 1 token = 1,000,000 base units.

Related resources

TRC-20 — standard overview
Contract example — full reference implementation
Issuing a TRC-20 token — deployment walkthrough
Interacting with TRC-20 contracts — read and write from a deployed TRC-20