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Merge pull request #5005 from ethereum/ecrecover_refer_address

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Add a link from ecrecover to address (typecast)
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Alex Beregszaszi 2018-09-18 11:08:45 +01:00 committed by GitHub
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docs/units-and-global-variables.rst
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@ -151,6 +151,11 @@ Mathematical and Cryptographic Functions
recover the address associated with the public key from elliptic curve signature or return zero on error recover the address associated with the public key from elliptic curve signature or return zero on error
(`example usage <https://ethereum.stackexchange.com/q/1777/222>`_) (`example usage <https://ethereum.stackexchange.com/q/1777/222>`_)
.. note::
Function ``ecrecover`` returns an ``address``, and not an ``address
payable``. See :ref:`address payable<address>` for conversion, in case you need
to transfer funds to the recovered address.
It might be that you run into Out-of-Gas for ``sha256``, ``ripemd160`` or ``ecrecover`` on a *private blockchain*. The reason for this is that those are implemented as so-called precompiled contracts and these contracts only really exist after they received the first message (although their contract code is hardcoded). Messages to non-existing contracts are more expensive and thus the execution runs into an Out-of-Gas error. A workaround for this problem is to first send e.g. 1 Wei to each of the contracts before you use them in your actual contracts. This is not an issue on the official or test net. It might be that you run into Out-of-Gas for ``sha256``, ``ripemd160`` or ``ecrecover`` on a *private blockchain*. The reason for this is that those are implemented as so-called precompiled contracts and these contracts only really exist after they received the first message (although their contract code is hardcoded). Messages to non-existing contracts are more expensive and thus the execution runs into an Out-of-Gas error. A workaround for this problem is to first send e.g. 1 Wei to each of the contracts before you use them in your actual contracts. This is not an issue on the official or test net.
.. index:: balance, send, transfer, call, callcode, delegatecall, staticcall .. index:: balance, send, transfer, call, callcode, delegatecall, staticcall