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Diffstat (limited to 'docs/frequently-asked-questions.rst')
| -rw-r--r-- | docs/frequently-asked-questions.rst | 38 |
1 files changed, 0 insertions, 38 deletions
diff --git a/docs/frequently-asked-questions.rst b/docs/frequently-asked-questions.rst index 8b655b0d..a569a896 100644 --- a/docs/frequently-asked-questions.rst +++ b/docs/frequently-asked-questions.rst @@ -143,44 +143,6 @@ arguments for you. See `ping.sol <https://github.com/fivedogit/solidity-baby-steps/blob/master/contracts/45_ping.sol>`_ and `pong.sol <https://github.com/fivedogit/solidity-baby-steps/blob/master/contracts/45_pong.sol>`_. -When returning a value of say ``uint`` type, is it possible to return an ``undefined`` or "null"-like value? -============================================================================================================ - -This is not possible, because all types use up the full value range. - -You have the option to ``throw`` on error, which will also revert the whole -transaction, which might be a good idea if you ran into an unexpected -situation. - -If you do not want to throw, you can return a pair:: - - pragma solidity >0.4.23 <0.6.0; - - contract C { - uint[] counters; - - function getCounter(uint index) - public - view - returns (uint counter, bool error) { - if (index >= counters.length) - return (0, true); - else - return (counters[index], false); - } - - function checkCounter(uint index) public view { - (uint counter, bool error) = getCounter(index); - if (error) { - // Handle the error - } else { - // Do something with counter. - require(counter > 7, "Invalid counter value"); - } - } - } - - Are comments included with deployed contracts and do they increase deployment gas? ================================================================================== |