Questions tagged [smart-contract]

Anything related to decentralized application (dApp) development, concepts, and possibilities with smart contracts, or technical questions for the development of smart contracts.

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What could be the reason for 'Error 3050008: Abort Called'

I'm getting the following error without any further description. What could be the issue for that? I'm performing some binary arithmetics when calling this action, are there any known problems with ...
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6 votes
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How to use checksum256 secondary index to get table rows

Does anyone know the correct way to get table rows using checksum256 (fixed_bytes<32>) secondary index through the get_table_rows RPC API? I found a way using key256, but key256 is deprecated ...
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require_auth() not working as expected

I adapted the hello contract, expanding with require_auth() and added an additional account oliver that should be able to execute the action hashin on behalf of the contract owner doctest1. I adjusted ...
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How to get current time in different versions of EOSIO

Depending on which version of EOSIO you use, there are different options available for finding the current time. What are they?
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2 votes
2 answers
643 views

Make a transfer inline

I would like to send SYS token owned by the smart contract account to a third party account when anyone call a specific action. I have tried the following code but I am getting an error: [[eosio::...
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How do I set my smart-contract / account to "immutable"?

What's the correct cleos command to yield the active/owner permissions of a deployed contract to "eosio.code", exclusively?
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`cleos get table` not returning vector<string>

I declare a vector vector<string> data inside a contract. Contract Code: book.emplace(_self, [&](struct wname &a){ a.name = fa.pubaddress; a.namehash = ...
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1 vote
1 answer
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How to convert a public key string to a eosio::publickey object inside a smart contract?

The smart contract takes a string as an input for the public key. I need to convert it into a public key object within the contract.
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3 answers
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Custom dispatcher new CDT

I'm having compilation issues when creating a custom dispatcher. I'm getting issues when calling EOSIO_DISPATCH. Is it related to changes in new CDT? class [[eosio::contract("mycontract")]] ...
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Multi_index issues

I'm getting a lot of errors related to multi_index after updating to the newest eosio.cdt. Here is part of my code related to hash. struct st_hash { capi_checksum256 hash; uint64_t expiration; ...
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Does EOSIO Have Native Contracts Built-Into Protocol Layer?

On the Bitshares site I read https://bitshares.org/technology/industrial-performance-scalability Based upon the lessons we learn from LMAX, we know that a virtual machine for a blockchain should be ...
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Issue while compiling smart contract - eosio.cdt

I have installed eosio.cdt in Ubuntu system by using commands from EOS Developers Portal wget https://github.com/EOSIO/eosio.cdt/releases/download/v1.4.1/eosio.cdt-1.4.1.x86_64.deb sudo apt install ./...
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What can prevent one from changing contract code?

I find one major characteristic of EOSIO is that the smart contract code is interchangeable, so that developers can easily fix any bugs or change its logic. But what if someone changes the code to ...
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cannot get latest state of table after modifying table in inline action

As shown with code below, I modify table in an inline action, and then want to get the latest data. But the data I get is not the latest. Why? void mycontract::myfunc() { action ( ...
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2 votes
1 answer
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How to have real-time communication in dapp?

How would a real-time 1v1 game work on the EOS Blockchain? I've noticed that many of the games/gambling dapps on EOS are mostly player vs. blockchain, like EOSBet. Could I have real-time updates to ...
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4 votes
2 answers
204 views

Require authorization with conditions require_auth(name1 OR name2)

Is there any possibility to implement conditional require_auth(<condition>) or what is a good practice to make contract accept invocations from a set of predetermined accounts? Is there any ...
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2 answers
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Is there a way to prevent me spending tokens until an action is called?

I am creating a smart contract but came to a halt when writing the code. Is there a way, in a smart contract, to prevent me from spending tokens transferred to me by another user through the smart ...
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2 answers
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How to avoid cpu usage limits

Task Compute some fields for all table rows when action called contract::priceupdate(price) Input data: Table with 10000 rows Problem Cpu limit 30ms so i cant update whole table in 1 transaction ...
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1 answer
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Passing the action name having return type to EOSIO_DISPATCH in EOSIO smart contract

I have following EOSIO smart contract: #include <eosiolib/eosio.hpp> #include <eosiolib/print.hpp> using namespace eosio; class random : public contract { public: using contract::...
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1 answer
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Example of resource staking from contract

I'm looking for any relevant code example or documentation describing how to make contract stake resources for some account. I'm aware of delegatebw function of cleos however, I need the following ...
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3 votes
1 answer
271 views

Deploy Contract from browser using eosjs

so I would like to deploy an EOS contract using eosjs. I encountered several problems (especially with converting the .abi and .wasm files). All the examples either use node (so fs is available) or an ...
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0 answers
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Where are deferred transaction errors logged to?

I'm trying to learn about deferred transactions. I'm creating a bogus deferred transaction that invokes a non-existent action "fakeaction": transaction out{}; out.actions.emplace_back(...
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1 answer
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Can a contract know the creation date of accounts?

Is the creation date of accounts part of consensus? Can I query it within contracts? If so, how to do it?
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533 views

How to list all balances of tokens managed by an eosio.token contract?

Let's say I have deployed the standard eosio.token contract to an account called "myeosiotoken," and I have used it to create an "ABC" token. Then, I issue 1,000 ABC to "someaccount1" and 2,000 ABC to ...
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1 vote
1 answer
131 views

How to extend the functionality of eosio.token?

I want to create an EOSIO token with additional functionality. For example, I want users to be able to claim() an additional token per day (since e.g. account creation date). Should I create a new ...
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1 answer
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Token transfer missing_auth_exception

{ "code":500,"message":"Internal Service Error", "error":{"code":3090004,"name":"missing_auth_exception", "what":"Missing required authority", "details":[{"message":"missing authority of thomsoimj21","...
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How to deploy a contract to api-kylin.eosasia.one testnet

I have written a helloworld contract and got compiled that successfully thomsonim123 is my kylin testnet account with some EOS when I want to deploy the contracct to the testnet I get few errors. ...
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1 answer
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Is it possible to overload contract actions?

I had a method: -- t.hpp -- [[eosio::action]] void exchange(); -- t.cpp -- void token::exchange() { ... } EOSIO_DISPATCH(eosio::token, (exchange)) and then decided that if a parameter were ...
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1 answer
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Authorisation failure with deferred transaction

I have a contract action that does some cleanup: void token::cleanup() { ... } that I want to run asynchronously from another action like this: schedule("cleanup", 10). my scheduling method looks ...
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0 answers
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Exception Details: 3080006 deadline_exception: Transaction took too long

I'm getting this error and have read all there is to read on the net (which isn't much) about it. mostly I see others complaining about this error when they run an action for the first time in my ...
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  • 495
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2 answers
314 views

Erasing records with for loops

if I want to erase a table: orderbook b(_self, _self.value); auto m = b.get_index<name("idxprod")>(); for (auto &i : m) { m.erase(i); } I get the error: Error 3160005: The table ...
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1 answer
311 views

How to sort a table?

I'm following this explanation https://developers.eos.io/eosio-cpp/v1.1.0/docs/multi-index-table-tutorial using v1.5.0 of the CDT. Here's what I've got: struct [[eosio::table]] order_struct { ...
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1 vote
1 answer
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Symbol stringification?

an action in my contract accepts an asset: void token::burn(asset a) which I want to print out: printf("Asset [%s] burnt\n", a.symbol.to_string()); except the symbol class does not offer ...
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1 vote
2 answers
51 views

Is there a way to check the histroy of a contract's table?

Is there a way to check the history after deleting the information in the table? For example, check yesterday's table information.
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0 votes
2 answers
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Asset instantiation woes

if I declare an asset: asset a(10, symbol("TST", 0); and I print it: a.print(); I get pretty much what I'd expect: TST the format's not quite right (10 TST would have been better), but ...
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1 vote
1 answer
110 views

Multiple print statements?

given the lack of debugging facilities in EOS contract development I add print() statements to my code, but I'm finding that only the first one gets printed, so: print("HERE\n"); print("HERE\n"); ...
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0 votes
1 answer
652 views

no member named 'print' in 'std::__1::basic_string<char>'

if I declare a string and attempt to print it like this: std::string s; eosio::print(s); the EOS compiler pukes: In file included from t.cpp:1: In file included from ./t.hpp:4: In file included ...
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1 vote
2 answers
155 views

Passing a string to an action?

I have an action that needs to operate on a string: void token::MyAction(std::string key); so I would expect I can make the call like this: cleos push action MyAccount MyAction '["burn"]' -p ...
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0 votes
2 answers
51 views

Referring to permissioned account within contract code?

I've created a table within a contract where I want to store user information. the .emplace() method's first parameter specifies the "scope" (I guess) for data to be stored and thus the user account ...
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0 votes
1 answer
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delay_sec is not accurate for deferred transaction

I have set some seconds but sometimes it is delayed more than 10 minutes. I know that delay_sec is not the accurate time because of the block production mechanism. The real time is much later than it ...
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1 vote
2 answers
45 views

Error about billed CPU time when set Hello World Smart Contract

My VM Spec (VMWare ESXI) CPU : Xeon CPU E5-2620 v2 @ 2.10GHz Memory : 8GB HDD : 70GB EOS 1.5.3 , EOS.CDT 1.4.1 Compile from Source Code with AutoBuild Scripts. I try to create first smart contract ...
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0 votes
1 answer
179 views

EOSIO: name.value secondary index returns end iterator, even though searched value exists in table

I've got a multi-index table going with two secondary indices: TABLE entry { uint64_t id = 0; eosio::name player; std::vector<uint16_t> allocation; ...
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1 vote
1 answer
91 views

Can a deferred transaction make the initial transaction fail

Imagine a user sending me some eosio.token to my contract and when I receive the notification, I start a new deferred transaction that fails later. Can the deferred transaction make the initial ...
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2 votes
1 answer
100 views

Multiple Inheritance within ABI files

I have various classes that use multiple inheritance, i.e.: class A { }; class B { }; class C : public A, public B { }; Single inheritance in an ABI file is possible using the base layer as ...
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0 votes
2 answers
264 views

Best way to read data from contract using eosjs or Cleos

How you read the data from your contracts, just by using actions? Or there is another way? Thanks!
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2 votes
3 answers
100 views

Updating existing token contract code

I have deployed a token on main net and called the create method to issue tokens. However, I would like to update the token code to add an extra feature. I can't find any information on the best ...
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2 votes
1 answer
185 views

Fixing a smart contract written in old version of eosio.cdt

I am using Ubuntu 18.04 LTS first of all. So I am trying to look up how to start building an EOS dApp, starting with this example on Github. Here is the link: https://github.com/eosasia/eos-todo I ...
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2 votes
2 answers
315 views

A possible alternative sign in/login process instead of firebase auth / amazon cognito using an eos contract?

I had the the idea of a secure alternative login process using an EOS smart contract instead of firebase or Amazon cognito. I would like to know if something like this feasible? My idea is somewhat ...
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1 vote
1 answer
53 views

In Eosbetdice contract, in the transfer action, why it is able to emplace a new row in this table?

In Eosbetdice contract, https://gitlab.com/EOSBetCasino/eosbetdice_public/blob/master/EOSBetDice.cpp#L193 The code of the contract in this line should be "eosio.token". I wonder why it doesn't get "...
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  • 121
0 votes
1 answer
64 views

Blacklisting specific addresses on token::transfer

I've issued a token using eosio.token standard contract. I want to prevent transfers to a number of specific accounts, for a limited time. Since it is temporary, I think I can simply hardcode the ...
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