> For the complete documentation index, see [llms.txt](https://contracts.synapseprotocol.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://contracts.synapseprotocol.com/elin/contracts-upgradeable-4.5.0/token/erc721/extensions/ierc721enumerableupgradeable.md). # IERC721EnumerableUpgradeable > ERC-721 Non-Fungible Token Standard, optional enumeration extension *See * ## Methods ### approve ```solidity function approve(address to, uint256 tokenId) external nonpayable ``` *Gives permission to `to` to transfer `tokenId` token to another account. The approval is cleared when the token is transferred. Only a single account can be approved at a time, so approving the zero address clears previous approvals. Requirements: - The caller must own the token or be an approved operator. - `tokenId` must exist. Emits an {Approval} event.* #### Parameters | Name | Type | Description | | ------- | ------- | ----------- | | to | address | undefined | | tokenId | uint256 | undefined | ### balanceOf ```solidity function balanceOf(address owner) external view returns (uint256 balance) ``` *Returns the number of tokens in `owner`'s account.* #### Parameters | Name | Type | Description | | ----- | ------- | ----------- | | owner | address | undefined | #### Returns | Name | Type | Description | | ------- | ------- | ----------- | | balance | uint256 | undefined | ### getApproved ```solidity function getApproved(uint256 tokenId) external view returns (address operator) ``` *Returns the account approved for `tokenId` token. Requirements: - `tokenId` must exist.* #### Parameters | Name | Type | Description | | ------- | ------- | ----------- | | tokenId | uint256 | undefined | #### Returns | Name | Type | Description | | -------- | ------- | ----------- | | operator | address | undefined | ### isApprovedForAll ```solidity function isApprovedForAll(address owner, address operator) external view returns (bool) ``` *Returns if the `operator` is allowed to manage all of the assets of `owner`. See {setApprovalForAll}* #### Parameters | Name | Type | Description | | -------- | ------- | ----------- | | owner | address | undefined | | operator | address | undefined | #### Returns | Name | Type | Description | | ---- | ---- | ----------- | | \_0 | bool | undefined | ### ownerOf ```solidity function ownerOf(uint256 tokenId) external view returns (address owner) ``` *Returns the owner of the `tokenId` token. Requirements: - `tokenId` must exist.* #### Parameters | Name | Type | Description | | ------- | ------- | ----------- | | tokenId | uint256 | undefined | #### Returns | Name | Type | Description | | ----- | ------- | ----------- | | owner | address | undefined | ### safeTransferFrom ```solidity function safeTransferFrom(address from, address to, uint256 tokenId) external nonpayable ``` *Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients are aware of the ERC721 protocol to prevent tokens from being forever locked. Requirements: - `from` cannot be the zero address. - `to` cannot be the zero address. - `tokenId` token must exist and be owned by `from`. - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}. - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. Emits a {Transfer} event.* #### Parameters | Name | Type | Description | | ------- | ------- | ----------- | | from | address | undefined | | to | address | undefined | | tokenId | uint256 | undefined | ### safeTransferFrom ```solidity function safeTransferFrom(address from, address to, uint256 tokenId, bytes data) external nonpayable ``` *Safely transfers `tokenId` token from `from` to `to`. Requirements: - `from` cannot be the zero address. - `to` cannot be the zero address. - `tokenId` token must exist and be owned by `from`. - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. Emits a {Transfer} event.* #### Parameters | Name | Type | Description | | ------- | ------- | ----------- | | from | address | undefined | | to | address | undefined | | tokenId | uint256 | undefined | | data | bytes | undefined | ### setApprovalForAll ```solidity function setApprovalForAll(address operator, bool _approved) external nonpayable ``` *Approve or remove `operator` as an operator for the caller. Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller. Requirements: - The `operator` cannot be the caller. Emits an {ApprovalForAll} event.* #### Parameters | Name | Type | Description | | ---------- | ------- | ----------- | | operator | address | undefined | | \_approved | bool | undefined | ### supportsInterface ```solidity function supportsInterface(bytes4 interfaceId) external view returns (bool) ``` *Returns true if this contract implements the interface defined by `interfaceId`. See the corresponding section] to learn more about how these ids are created. This function call must use less than 30 000 gas.* #### Parameters | Name | Type | Description | | ----------- | ------ | ----------- | | interfaceId | bytes4 | undefined | #### Returns | Name | Type | Description | | ---- | ---- | ----------- | | \_0 | bool | undefined | ### tokenByIndex ```solidity function tokenByIndex(uint256 index) external view returns (uint256) ``` *Returns a token ID at a given `index` of all the tokens stored by the contract. Use along with {totalSupply} to enumerate all tokens.* #### Parameters | Name | Type | Description | | ----- | ------- | ----------- | | index | uint256 | undefined | #### Returns | Name | Type | Description | | ---- | ------- | ----------- | | \_0 | uint256 | undefined | ### tokenOfOwnerByIndex ```solidity function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256) ``` *Returns a token ID owned by `owner` at a given `index` of its token list. Use along with {balanceOf} to enumerate all of `owner`'s tokens.* #### Parameters | Name | Type | Description | | ----- | ------- | ----------- | | owner | address | undefined | | index | uint256 | undefined | #### Returns | Name | Type | Description | | ---- | ------- | ----------- | | \_0 | uint256 | undefined | ### totalSupply ```solidity function totalSupply() external view returns (uint256) ``` *Returns the total amount of tokens stored by the contract.* #### Returns | Name | Type | Description | | ---- | ------- | ----------- | | \_0 | uint256 | undefined | ### transferFrom ```solidity function transferFrom(address from, address to, uint256 tokenId) external nonpayable ``` *Transfers `tokenId` token from `from` to `to`. WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible. Requirements: - `from` cannot be the zero address. - `to` cannot be the zero address. - `tokenId` token must be owned by `from`. - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. Emits a {Transfer} event.* #### Parameters | Name | Type | Description | | ------- | ------- | ----------- | | from | address | undefined | | to | address | undefined | | tokenId | uint256 | undefined | ## Events ### Approval ```solidity event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId) ``` #### Parameters | Name | Type | Description | | ------------------ | ------- | ----------- | | owner `indexed` | address | undefined | | approved `indexed` | address | undefined | | tokenId `indexed` | uint256 | undefined | ### ApprovalForAll ```solidity event ApprovalForAll(address indexed owner, address indexed operator, bool approved) ``` #### Parameters | Name | Type | Description | | ------------------ | ------- | ----------- | | owner `indexed` | address | undefined | | operator `indexed` | address | undefined | | approved | bool | undefined | ### Transfer ```solidity event Transfer(address indexed from, address indexed to, uint256 indexed tokenId) ``` #### Parameters | Name | Type | Description | | ----------------- | ------- | ----------- | | from `indexed` | address | undefined | | to `indexed` | address | undefined | | tokenId `indexed` | uint256 | undefined | --- # Agent Instructions This documentation is published with GitBook. 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