From a29aaa3776f028d635307d6ef9a889ea3a01427d Mon Sep 17 00:00:00 2001 From: Denton Liu Date: Wed, 25 May 2016 10:44:35 -0400 Subject: [PATCH] Added section on address-related constants --- docs/units-and-global-variables.rst | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/docs/units-and-global-variables.rst b/docs/units-and-global-variables.rst index d0a60d288..594807c00 100644 --- a/docs/units-and-global-variables.rst +++ b/docs/units-and-global-variables.rst @@ -111,6 +111,21 @@ same as ``sha3(uint16(0x12))``. It might be that you run into Out-of-Gas for ``sha256``, ``ripemd160`` or ``ecrecover`` on a *private blockchain*. The reason for this is that those are implemented as so-called precompiled contracts and these contracts only really exist after they received the first message (although their contract code is hardcoded). Messages to non-existing contracts are more expensive and thus the execution runs into an Out-of-Gas error. A workaround for this problem is to first send e.g. 1 Wei to each of the contracts before you use them in your actual contracts. This is not an issue on the official or test net. +.. index:: send, balance + +Address Related +--------------- + +``
.balance`` (``uint256``): + balance of the address in Wei +``
.send(uint256) returns (bool)``: + send given amount of Wei to address, returns ``false`` on failure + +.. warning:: + Since it is possible for calls to ``send`` to fail, such as + if there are insufficient funds, it is good practice to + check the return value whenever calling ``send``. + .. index:: this, selfdestruct Contract Related