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Diffstat (limited to 'docs/control-structures.rst')
| -rw-r--r-- | docs/control-structures.rst | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/docs/control-structures.rst b/docs/control-structures.rst index 7e3027a0..7024a684 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -473,7 +473,7 @@ Catching exceptions is not yet possible. In the following example, you can see how ``require`` can be used to easily check conditions on inputs and how ``assert`` can be used for internal error checking. Note that you can optionally provide -a message string for require, but not for assert. +a message string for ``require``, but not for ``assert``. :: @@ -539,9 +539,13 @@ The following example shows how an error string can be used together with revert } } -The provided string will be abi-encoded together with a uint value that will always be zero. -This means that if a string ``x`` is provided, ``(0, x)`` will be encoded as if a function with arguments -``(uint256, string)`` was called. This zero is used as a version identifier. Future extensions -of this feature might provide actual exception payload of dynamic type and this number could be used -to encode the type or also as a simple numeric error code. Until this is specified, a zero will -be used in all cases.
\ No newline at end of file +The provided string will be :ref:`abi-encoded <ABI>` as if it were a call to a function ``Error(string)``. +In the above example, ``revert("Not enough Ether provided.");`` will cause the following hexadecimal data be +set as error return data: + +.. code:: + + 0x08c379a0 // Function selector for Error(string) + 0x0000000000000000000000000000000000000000000000000000000000000020 // Data offset + 0x000000000000000000000000000000000000000000000000000000000000001a // String length + 0x4e6f7420656e6f7567682045746865722070726f76696465642e000000000000 // String data |