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Documentation for function call options.

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chriseth
2020-01-23 21:20:01 +01:00
parent 893fb4d05b
commit 981ed5f773
4 changed files with 96 additions and 19 deletions
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docs/types/value-types.rst
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@@ -276,17 +276,17 @@ Example::
arbitrary arguments and would also handle a first argument of type
``bytes4`` differently. These edge cases were removed in version 0.5.0.
It is possible to adjust the supplied gas with the ``.gas()`` modifier::
It is possible to adjust the supplied gas with the ``gas`` modifier::
address(nameReg).call.gas(1000000)(abi.encodeWithSignature("register(string)", "MyName"));
address(nameReg).call{gas: 1000000}(abi.encodeWithSignature("register(string)", "MyName"));
Similarly, the supplied Ether value can be controlled too::
address(nameReg).call.value(1 ether)(abi.encodeWithSignature("register(string)", "MyName"));
address(nameReg).call{value: 1 ether}(abi.encodeWithSignature("register(string)", "MyName"));
Lastly, these modifiers can be combined. Their order does not matter::
address(nameReg).call.gas(1000000).value(1 ether)(abi.encodeWithSignature("register(string)", "MyName"));
address(nameReg).call{gas: 1000000, value: 1 ether}(abi.encodeWithSignature("register(string)", "MyName"));
In a similar way, the function ``delegatecall`` can be used: the difference is that only the code of the given address is used, all other aspects (storage, balance, ...) are taken from the current contract. The purpose of ``delegatecall`` is to use library code which is stored in another contract. The user has to ensure that the layout of storage in both contracts is suitable for delegatecall to be used.
@@ -297,7 +297,8 @@ Since byzantium ``staticcall`` can be used as well. This is basically the same a
All three functions ``call``, ``delegatecall`` and ``staticcall`` are very low-level functions and should only be used as a *last resort* as they break the type-safety of Solidity.
The ``.gas()`` option is available on all three methods, while the ``.value()`` option is not supported for ``delegatecall``.
The ``gas`` option is available on all three methods, while the ``value`` option is not
supported for ``delegatecall``.
.. note::
All contracts can be converted to ``address`` type, so it is possible to query the balance of the
@@ -635,8 +636,12 @@ External (or public) functions have the following members:
* ``.address`` returns the address of the contract of the function.
* ``.selector`` returns the :ref:`ABI function selector <abi_function_selector>`
* ``.gas(uint)`` returns a callable function object which, when called, will send the specified amount of gas to the target function. See :ref:`External Function Calls <external-function-calls>` for more information.
* ``.value(uint)`` returns a callable function object which, when called, will send the specified amount of wei to the target function. See :ref:`External Function Calls <external-function-calls>` for more information.
* ``.gas(uint)`` returns a callable function object which, when called, will send
the specified amount of gas to the target function. Deprecated - use ``{gas: ...}`` instead.
See :ref:`External Function Calls <external-function-calls>` for more information.
* ``.value(uint)`` returns a callable function object which, when called, will
send the specified amount of wei to the target function. Deprecated - use ``{value: ...}`` instead.
See :ref:`External Function Calls <external-function-calls>` for more information.
Example that shows how to use the members::
@@ -651,6 +656,8 @@ Example that shows how to use the members::
function g() public {
this.f.gas(10).value(800)();
// New syntax:
// this.f{gas: 10, value: 800}()
}
}