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| -rw-r--r-- | docs/units-and-global-variables.rst | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/docs/units-and-global-variables.rst b/docs/units-and-global-variables.rst index d0a60d28..594807c0 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 +--------------- + +``<address>.balance`` (``uint256``): + balance of the address in Wei +``<address>.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 |