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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how do i use current_time_point() to store date in eos table

I have tried This way and its not getting store,infact its giving me error,please sugguest if im making any mistake. error: use of undeclared identifier 'current_time_point'; did you mean '...
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1answer
51 views

How to remove deployed smart contract?

I want to sorta "undeploy" smart contract as it was not deployed ever. If it is possible, I hope it will cleanup account's RAM. And I'm not talking about freezing .
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1answer
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COMPILATION ERROR error: non-type template argument is not a constant expression

what is causing this error while im compiling ? struct [[eosio::table]] requestForLoan{ uint64_t req_id; name borr_name; uint64_t borr_id; name uwr_name; uint64_t uwr_id;...
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2answers
42 views

Zero amount transfer?

I just want to use EOSIO as a DB of some events by sending transactions when other events fire. Is it possible to send ZERO amount transfers? The events are millions a day, and I don't know how to ...
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1answer
84 views

check (within smart contract) if an account is a proxy

How can I verify within a smart contract that an account is a proxy? I know that there is a function is_account, which verifies that a name is an existing account. Is there a way to check if an ...
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1answer
842 views

assertion failure with message: no balance object found

This error message occurs when trying to do a transfer: assertion failure with message: no balance object found What causes it and how can it be avoided?
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2answers
461 views

Why is [[eosio::on_notify(“eosio.token::transfer”)]] not working?

Network: kylin testnet. I transferred eos to this contract, but it the "deposit" function was not called. What do I miss?
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1answer
55 views

Is there a way to call a multisig approval programmatically from within a contract?

Following scenario: There's an action which requires 3 signatures - two are 'normal accounts' and the third one is like 'system or robot', which does some verifications from within the smart contract....
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2answers
166 views

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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36 views

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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2answers
242 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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2answers
59 views

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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95 views

A contract without struct and multi index table

Actually, I am looking to create a contract in which a variable can be set and later on can be retrieved. All the contracts available there involves struct and multi index table. In EOS, is it ...
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2answers
878 views

Convert string to float or double

I am trying to convert a string to a float or double, however none of the standard C/C++ methods seem to work. I have tried: atof strtof strtod sscanf In each case, I get an error message when ...
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1answer
138 views

Can smart contract code query the block chain?

A EOS C++ smart contract can have code that query and iterate through the blockchain, to get the actions and transactions and related data? In eos.js you can do eos.getActions(accountName) but inside ...
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1answer
29 views

Traverse multi-index table through non-primary value and delete the record

Below is my smart contract: #include <eosio/eosio.hpp> #include <eosio/print.hpp> #include <eosio/system.hpp> #include <string> using namespace eosio; using std::string; ...
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1answer
26 views

How much RAM does a smart contract consume?

I have a smart contract compiled resulting in a 10,961 Bytes wasm file and a 2,372 Bytes abi file. However, when deploying the contract on chain it consumes about 110,000 Bytes which is almost 10x the ...
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1answer
29 views

Compiling smart contract not getting done

I have a setup of multi-node of 4 peers blockchain. Blockchain is running, few days before I deployed the smart contract and using it to save data on the blockchain. Now, I did some changes to the ...
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1answer
20 views

Issues regarding the update of a staking contract

Suppose that we need a token staking mechanism (similar to the stake and lock function introduced in the EOSIO training). Someone owns that contract. Now the question is: How would the rest of the ...
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1answer
24 views

Is it possible to get the initiating contract name from a token transfer?

When an external account transfers tokens to my account (which has a contract with an "on_notify" action for incoming transfers), is there any way I can get the name of the contract that ...
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1answer
27 views

What does 'datastream<const char*>' mean in this code?

From this tutorial addressbook(name receiver, name code, datastream<const char*> ds): contract(receiver, code, ds) I'm not familiar with 'datastream' and Googling isn't turning up any precise ...
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1answer
45 views

Calling external action with 'action_wrapper' and 'action'

In contract we have two way to call another action: Use 'action' action(permission_level{get_self(), eosio::name{"active"}}, eosio::name{"eosio"}, ...
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1answer
110 views

Convert type string to type checksum256

fist off let me get this strait, yes I know the dangers of memo parsing, yes I am aware of the vulnerabilities that can be created from doing such a process, so please there is no need to lecture me ...
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1answer
31 views

eoslime test not saving data in table

This is my first experience with eoslime as I want to do unit testing for smart contracts. Not much experienced with nodejs .I am following eoslime documentation: https://docs.eoslime.limechain.tech/...
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1answer
29 views

Wrong table name in scope response

My contract has two tables mcat and mcatmig. Problem: scope request return wrong table name mcat........1 instead of mcatmig: % cleos get scope teresacode { "rows": [{ "code": "teresacode", "...
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1answer
45 views

How to check authorization for a particular account in EOS smart contract?

I want to write an EOS smart contract to manage users data. I need that only some admin account will able to add, update and delete users and the particular user can only update data. Can I check ...
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1answer
33 views

Complex smart contract for rule based auction in multiple currencies

The imagined application allows users to participate in an auction and make bids in cryptocurrencies. There are several behavioral rules that control the execution of the auction and determine the ...
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1answer
26 views

Take output from GetActions and send to database using eossharp

I am using eos-sharp to get data from the eos smart contract. I am trying to get actions data by using: var resultaction = await eos.GetActions("dqzmember", 0, 30); I need information from ...
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1answer
50 views

how to save data in mongodb from eos smart contract?

I am getting the actions log data using an action constructor in a smart contract. I need to save this data in MongoDB from the smart contract. How can I do this? I didn't get exactly my required ...
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1answer
19 views

How to access and manipulate tables when using native unit tests?

I am trying to write unit tests for functions in a smart contract that require access to tables within the smart contract. I tried to set this up using the hello_test.cpp code as a base and when I get ...
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1answer
55 views

How do I record LOG in eosio smart contract?

I deployed and tested eosio smart contract. I want to record the logs of a smart contract using the web API. How can I do this? I searched but didn't get any satisfying answer. I tried to get logs by ...
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1answer
125 views

What is the difference between std::string and eosio::string?

Why should I use eosio::string over std::string? What are the use cases where it would make a difference?
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1answer
32 views

Static values get mangled

if you run the following (on eosio v1.8.4): #include <eosio/eosio.hpp> #include <eosio/asset.hpp> namespace eosio { class UTL { public: static name code; ...
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1answer
32 views

Function not giving expected output Eos smart contract

My contract .Cpp part void mainloan::adduwr(name acc_name, double interest, uint64_t loan_amount ) { print("Adding underwriter", acc_name); // require_auth( _self ); uwr_table.emplace(get_self(...
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1answer
97 views

Convert String to double (flaot32/float64) in EOSIO [duplicate]

serialize support for float types is not added in flutter and thats why i have to come to this way,so if anyone have any working example for this,ill be really thankful for that. I have tried this ...
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1answer
295 views

How can we retrieve table data with secondary Index in EOS table

this is my table struct [[eosio::table]] payment_made { uint64_t pay_id; uint64_t loan_id; uint64_t pay_amunt; time_point_sec pay_date_req; time_point_sec pay_date_approve; ...
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1answer
47 views

COMPILATION ERROR error: static_assert failed "Something went wrong. Please report this issue to the github

Getting an error when the code reaches this particular function. Is there something obvious I am missing here? Kindly Note this is Deferred transaction Please ask if anything else is required from ...
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1answer
222 views

Can we store date on eosio table?

Is there any direct datatype in eosio to store date? and if not then how can we store dates in eosio table? void mainloan::paymentConfirm(uint64_t pay_id,uint64_t pay_date,double pay_amunt,name from ...
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2answers
367 views

How to loop a multi_index table in a smart contract

I have very simple table items with the following structure: struct [[eosio::table]] item { uint64_t id; uint64_t state; string description; uint64_t primary_key() ...
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1answer
58 views

Can I use Timers?

I know that there's no timer in other smart contracts and even this is not possible in regular blockchains. But, EOS uses C++, and they already did lots stuffs which makes smart contracts more usable. ...
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1answer
237 views

eosio-cpp command not found error?

When I am trying to run hello world smart contract using a command eosio-cpp -abigen -o hello.wasm hello.cpp shown an error eosio-cpp: command not found?
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1answer
28 views

EOS Token contract audit issue

My token contract was done by a third party vendor that did not share source code of the token contract with me. Can you help me on how to find the code, so that I can submit it to you for audit ...
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1answer
32 views

Acting on upon a receipt of a token, using v1.6 c++ libraries

Let's say I wanted to act upon receipt of a token and/or a message to a smart contract. Previous versions of EOS used the apply function to do this, however as of v1.6 things have changed to pure cpp ...
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2answers
658 views

Using find on multi index table

I have a table defined as the following: struct [[ eosio::table, eosio::contract("voting") ]] identity { uint64_t key; key256 identityHash; time_point_sec createdAt; uint64_t ...
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1answer
40 views

How is memory aligned in the EOSIO smart contract consensus memory?

Are there any memory savings if I declare a table record that has, say, a 64-bit integer (occupies 8 bytes) and a 16-bit integer (occupies 2 bytes)? Or is it aligned at 64 bits and said record would ...
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1answer
55 views

Stake EOS and then unstake

Is there any documentation on staking or unstaking EOS using smart contracts? I basically want to provide an escrow service where the seller needs to stake the value of the item and the buyer stakes ...
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1answer
53 views

Is there any API in EOS Smart Contract to decrypt message? [duplicate]

I would like to create a smart contract that would be able to decrypt some symmetrically encrypted message. Here is the scenario: Party "A" sends a message encrypted with key "123456" to ...
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2answers
123 views

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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3answers
367 views

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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1answer
126 views

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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