Mastering Blockchain Programming with Solidity

ERC721 inherits from ERC165

The ERC721 contract inherits from the ERC165 contract, which contains its implementation. ERC165 also inherits from IERC165, which is the interface definition for ERC165 standard interface detection. The ERC165 contract inheritance is defined as follows:

contract ERC165 is IERC165 {

As we have discussed, ERC165 is used for standard interface detection, meaning that it allows the client application/contract to know whether a particular function is available to call on the contract. The contract defines the following function:

function supportsInterface(bytes4 interfaceId) external view returns (bool)

Using this function, we can pass the first four bytes of the function signature that the caller wants to check whether ...