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1500 questions
11
votes
2 answers
Check if Contract variable is undefined
How can I check if an Contract variable is undefined in Solidity?
arodriguezdonaire
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11
votes
3 answers
Visual Studio Code Ethereum tutorial
Are there any tutorials on how to use MS Visual Studio Code to write contracts in solidity?
Kizito
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11
votes
2 answers
Anonymous function in Solidity example code
I'm following this link - https://ethereum.org/token to learn Solidity. The example contract implementation has the following line which I don't understand.
Can someone please explain what is this function intended to do? When would it be called?…
navpal
- 362
- 2
- 7
11
votes
2 answers
trying to use web3-utils but not working
Trying to use web3-utils.
I installed the package via NPM , however, I am getting the error that sha3 is undefined..
TypeError: Cannot read property 'sha3' of undefined
at C:\block2\deliver.js:12:28
at Layer.handle [as handle_request]…
Dino Anastos
- 847
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11
votes
3 answers
Internal compiler error: Accessors for mapping with dynamically-sized keys not yet implemented
I have a mapping(string => Person) public map:
struct Person {
string name;
string description;
address primaryAddress;
string linkToWebsite;
string linkToPicture;
address secondaryAddress;
…
arodriguezdonaire
- 3,027
- 3
- 20
- 37
11
votes
3 answers
How to get an ERC20 token listed in etherscan.io
In etherscan.io, under the TOKEN drop down menu, there is a list of tokens,
and it is indicated that they all are ERC20 standard tokens
1) How do they get listed? Do we have to register a new ERC20 token somewhere or are they automatically…
jfjobidon
- 763
- 2
- 11
- 25
11
votes
1 answer
Is it possible to create ICO crowdsale seamlessly accepting multiple assets?
Most of the ICO crowdsales accept ETH only.
Some accept BTC.
Very few accept other assets.
I was thinking about creating crowdsale that would accept as many assets as possible.
While creating, monitoring, securing wallet for each asset might not…
Mars Robertson
- 1,011
- 1
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11
votes
1 answer
Truffle migrate vs Truffle deploy
Is there any difference between truffle migrate and truffle deploy, as of now what I observed is both the command perform deployment on desired networks
one recognizable difference which we can see in console is,
when we run
truffle…
SwapnilKumbhar
- 763
- 1
- 11
- 31
11
votes
2 answers
What diagrams exist to illustrate the Ethereum blockchain creation process?
I have found the below diagram (and this explanation) useful in understanding how blockchains work in general:
[Illustration by Matthäus Wander (Wikimedia)]
This answer goes on to say that
Ethereum's actual blockchain structure is somewhat more…
Lee
- 8,548
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- 80
11
votes
1 answer
Can I unlock an account using JSON-RPC?
The only way I can work with ETH is through --rpc mode. Normally I would prefer to use the Python interface.
But I found myself in a situation where the RPC is very limited. For example, I can't create or unlock an account.
Are these all the…
yanik
- 473
- 6
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11
votes
2 answers
Secure paper wallet creation for ETH using JS
I am about to start the process of transferring my ETH to paper wallets for safe keeping. Currently the funds are stored on an online exchange. History shows that this is a very bad idea. It is not much, but my threat-model is only on loosing the…
ST2OD
- 213
- 1
- 6
11
votes
0 answers
Guidelines for designing contracts to handle bugfixes?
Most introductory guides for contract design talk about creating "mortal" contracts (contracts that include some function that triggers a suicide() call), but what about if that contract was for some sort of sub-currency (Fungible Token/FT)? Is it…
MidnightLightning
- 2,988
- 16
- 28
11
votes
3 answers
What is the difference between testrpc and EtherSim?
These are both "faux-blockchains" for development purposes. Both are recommended from various people as a good tool when developing in truffle. And I even think both are being developed by the same people.
But I'm really having trouble finding which…
max
- 2,324
- 3
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11
votes
6 answers
Where can I download the Mist browser? (NOT the Ethereum wallet)
I want to download the Mist browser (as opposed to the Ethereum Wallet accessible via ethereum.org) but can't find a link.
The Github repo (https://github.com/ethereum/mist) and latest release page has a link for the Ethereum Wallet but not for the…
user712
11
votes
1 answer
Decode JSON RPC result
How do I convert the result returned from a JSON-RPC eth_call from my geth client?
This is the call:
curl -X POST --data '{"jsonrpc":"2.0","method":"eth_call","params":[{"to":"0x86312d97c0dd3fd9202fdbdec434f36ee1b30720", "data":"0x18160ddd"},…
Jupiter
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