From 2af949baaa31c328060008fe5b4dc251657f3d9d Mon Sep 17 00:00:00 2001 From: Alex Beregszaszi Date: Fri, 25 Aug 2017 11:12:26 +0100 Subject: Explain the limitations of view and pure --- docs/contracts.rst | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/docs/contracts.rst b/docs/contracts.rst index 973386d5..ef09d935 100644 --- a/docs/contracts.rst +++ b/docs/contracts.rst @@ -469,6 +469,17 @@ View Functions Functions can be declared ``view`` in which case they promise not to modify the state. +The following statements are considered modifying the state: + +#. Writing to state variables. +#. :ref:`Emitting events. `. +#. :ref:`Creating other contracts `. +#. Using ``selfdestruct``. +#. Sending Ether via calls. +#. Calling any function not marked ``view`` or ``pure``. +#. Using low-level calls. +#. Using inline assembly that contains certain opcodes. + :: pragma solidity ^0.4.16; @@ -496,6 +507,13 @@ Pure Functions Functions can be declared ``pure`` in which case they promise not to read from or modify the state. +In addition to the list of state modifying statements explained above, the following are considered reading from the state: +#. Reading from state variables. +#. Accessing ``this.balance`` or ``
.balance``. +#. Accessing any of the members of ``block``, ``tx``, ``msg`` (with the exception of ``msg.sig`` and ``msg.data``). +#. Calling any function not marked ``pure``. +#. Using inline assembly that contains certain opcodes. + :: pragma solidity ^0.4.16; -- cgit