diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/assembly.rst | 2 | ||||
| -rw-r--r-- | docs/control-structures.rst | 6 | ||||
| -rw-r--r-- | docs/miscellaneous.rst | 4 | ||||
| -rw-r--r-- | docs/units-and-global-variables.rst | 6 |
4 files changed, 15 insertions, 3 deletions
diff --git a/docs/assembly.rst b/docs/assembly.rst index 79137b7e..23ccfcbe 100644 --- a/docs/assembly.rst +++ b/docs/assembly.rst @@ -248,6 +248,8 @@ In the grammar, opcodes are represented as pre-defined identifiers. +-------------------------+------+-----------------------------------------------------------------+ | return(p, s) | `-` | end execution, return data mem[p..(p+s)) | +-------------------------+------+-----------------------------------------------------------------+ +| revert(p, s) | `-` | end execution, revert state changes, return data mem[p..(p+s)) | ++-------------------------+------+-----------------------------------------------------------------+ | selfdestruct(a) | `-` | end execution, destroy current contract and send funds to a | +-------------------------+------+-----------------------------------------------------------------+ | invalid | `-` | end execution with invalid instruction | diff --git a/docs/control-structures.rst b/docs/control-structures.rst index 1c7d71f2..df8ac729 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -396,7 +396,11 @@ Currently, Solidity automatically generates a runtime exception in the following #. If your contract receives Ether via a public getter function. #. If you call a zero-initialized variable of internal function type. -Internally, Solidity performs an "invalid jump" when a user-provided exception is thrown. In contrast, it performs an invalid operation +While a user-provided exception is generated in the following situations: +#. Calling ``throw``. +#. The condition of ``assert(condition)`` is not met. + +Internally, Solidity performs a revert operation (instruction ``0xfd``) when a user-provided exception is thrown. In contrast, it performs an invalid operation (instruction ``0xfe``) if a runtime exception is encountered. In both cases, this causes the EVM to revert all changes made to the state. The reason for this is that there is no safe way to continue execution, because an expected effect did not occur. Because we want to retain the atomicity of transactions, the safest thing to do is to revert all changes and make the whole transaction diff --git a/docs/miscellaneous.rst b/docs/miscellaneous.rst index 47650067..3c57507e 100644 --- a/docs/miscellaneous.rst +++ b/docs/miscellaneous.rst @@ -435,7 +435,7 @@ The following is the order of precedence for operators, listed in order of evalu | *16* | Comma operator | ``,`` | +------------+-------------------------------------+--------------------------------------------+ -.. index:: block, coinbase, difficulty, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, now, gas price, origin, keccak256, ripemd160, sha256, ecrecover, addmod, mulmod, cryptography, this, super, selfdestruct, balance, send +.. index:: block, coinbase, difficulty, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, now, gas price, origin, assert, revert, keccak256, ripemd160, sha256, ecrecover, addmod, mulmod, cryptography, this, super, selfdestruct, balance, send Global Variables ================ @@ -453,6 +453,7 @@ Global Variables - ``now`` (``uint``): current block timestamp (alias for ``block.timestamp``) - ``tx.gasprice`` (``uint``): gas price of the transaction - ``tx.origin`` (``address``): sender of the transaction (full call chain) +- ``revert()``: abort execution and revert state changes - ``keccak256(...) returns (bytes32)``: compute the Ethereum-SHA-3 (Keccak-256) hash of the (tightly packed) arguments - ``sha3(...) returns (bytes32)``: an alias to `keccak256()` - ``sha256(...) returns (bytes32)``: compute the SHA-256 hash of the (tightly packed) arguments @@ -460,6 +461,7 @@ Global Variables - ``ecrecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) returns (address)``: recover address associated with the public key from elliptic curve signature, return zero on error - ``addmod(uint x, uint y, uint k) returns (uint)``: compute ``(x + y) % k`` where the addition is performed with arbitrary precision and does not wrap around at ``2**256`` - ``mulmod(uint x, uint y, uint k) returns (uint)``: compute ``(x * y) % k`` where the multiplication is performed with arbitrary precision and does not wrap around at ``2**256`` +- ``assert(bool condition)``: throws if the condition is false - ``this`` (current contract's type): the current contract, explicitly convertible to ``address`` - ``super``: the contract one level higher in the inheritance hierarchy - ``selfdestruct(address recipient)``: destroy the current contract, sending its funds to the given address diff --git a/docs/units-and-global-variables.rst b/docs/units-and-global-variables.rst index dd3d4be8..72741b67 100644 --- a/docs/units-and-global-variables.rst +++ b/docs/units-and-global-variables.rst @@ -79,11 +79,13 @@ Block and Transaction Properties You can only access the hashes of the most recent 256 blocks, all other values will be zero. -.. index:: keccak256, ripemd160, sha256, ecrecover, addmod, mulmod, cryptography, this, super, selfdestruct, balance, send +.. index:: assert, revert, keccak256, ripemd160, sha256, ecrecover, addmod, mulmod, cryptography, this, super, selfdestruct, balance, send Mathematical and Cryptographic Functions ---------------------------------------- +``assert(bool condition)``: + throws if the condition is not met. ``addmod(uint x, uint y, uint k) returns (uint)``: compute ``(x + y) % k`` where the addition is performed with arbitrary precision and does not wrap around at ``2**256``. ``mulmod(uint x, uint y, uint k) returns (uint)``: @@ -98,6 +100,8 @@ Mathematical and Cryptographic Functions compute RIPEMD-160 hash of the (tightly packed) arguments ``ecrecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) returns (address)``: recover the address associated with the public key from elliptic curve signature or return zero on error +``revert()``: + abort execution and revert state changes In the above, "tightly packed" means that the arguments are concatenated without padding. This means that the following are all identical:: |