getApproveduint256

getApproveduint256 generally refers to the getApproved(uint256 tokenId) function in the ERC-721 non-fungible token standard. It is a view function that returns the address approved to transfer a specific token ID on behalf of its owner.

The function signature in typical implementations is: function getApproved(uint256 tokenId) external view returns (address operator). It provides a single address: the account that has been approved to transfer that particular token. If no address has been approved for the token, the function returns the zero address. Note that this reflects only the approval for that specific token and not for all of the owner’s tokens.

Existence and approval state are important: getApproved requires the tokenId to exist; querying for a nonexistent token usually reverts with an error defined by the contract (for example, “ERC721: approved query for nonexistent token”). Approvals for a token can be granted with approve(address to, uint256 tokenId) or cleared by a transfer or by re-approving to a different address. Importantly, approvals granted for a token are typically cleared automatically when the token is transferred to a new owner.

Relationship to other mechanisms is essential: isApprovedForAll(address owner, address operator) indicates whether an operator has permission to manage all tokens of an owner. getApproved only reflects the designated approved address for a single token, not the broader operator status.

In practice, getApproved(uint256 tokenId) enables marketplaces, wallets, and other contracts to determine whether a given address is authorized to transfer a specific token without requiring a full transfer.