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In Solidity function signatures are 4 bytes long and the formula to generate it is to hash it with the keccak256 function, like so:

bytes4(keccak256(“setA(uint256)”))

bytes4(keccak256("setA(uint256)"))

The first 4 bytes of msg.datamsg.data are the method signature. How can I extract those 4 bytes from msg`msg.data (using Solidity of course)?

In Solidity function signatures are 4 bytes long and the formula to generate it is to hash it with the keccak256 function, like so:

bytes4(keccak256(“setA(uint256)”))

The first 4 bytes of msg.data are the method signature. How can I extract those 4 bytes from msg.data (using Solidity of course)?

In Solidity function signatures are 4 bytes long and the formula to generate it is to hash it with the keccak256 function, like so:

bytes4(keccak256("setA(uint256)"))

The first 4 bytes of msg.data are the method signature. How can I extract those 4 bytes from `msg.data (using Solidity of course)?

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asked Nov 6, 2018 at 8:43

How to extract function signature from msg.data

In Solidity function signatures are 4 bytes long and the formula to generate it is to hash it with the keccak256 function, like so:

bytes4(keccak256(“setA(uint256)”))

The first 4 bytes of msg.data are the method signature. How can I extract those 4 bytes from msg.data (using Solidity of course)?

solidity