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Example showing how to use DELEGATECALL
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| // Author: Nick Mudge (https://twitter.com/mudgen) | |
| // This is part of my tweet thread, "Six things you need to know to use DELEGATECALL safely": https://twitter.com/mudgen | |
| // Shows how to use DELEGATECALL | |
| // Using OpenZeppelin's Address library check to see if | |
| // myContract has code. | |
| require(Address.isContract(myContractAddress), "Address has no code"); | |
| // Set function argument we are going to use. | |
| uint myArg = 10; | |
| // Create the function call with argument. | |
| bytes memory functionCall = abi.encodeWithSignature("myFunction(uint256)", myArg); | |
| // Execute delegatecall | |
| ( | |
| bool success, | |
| bytes memory result | |
| ) = myContractAddress.delegatecall(functionCall); | |
| // If the function call succeeded | |
| if(success) { | |
| // We know that "myFunction" returns an | |
| // uint256 so we decode it and return it. | |
| return abi.decode(result, (uint256)); | |
| } | |
| else { | |
| // If function did not succeed then revert with | |
| // error message if there is one. | |
| if (result.length > 0) { | |
| // bubble up the error | |
| revert(string(result)); | |
| } else { | |
| revert("myFunction had an error"); | |
| } | |
| } | |
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