Questions tagged [c++]

General purpose programming language.

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16 views

add mysql dependency configure.ac bitcoin

i am working on bitcoin code, my aim is to move blockchain data to relational db but i am not able to resolve mysql dependency for different platform, platform includes mac and ubuntu. I have tried ...
0
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1answer
26 views

Where is the code which rejects transactions with insuffisent balance?

Simple question but I can’t find the answer again. Where is the code which rejects transactions when the value of inputs is below the value of outputs (because I think to recall that check works like ...
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1answer
110 views

How happens the serealization the data in the file blkxxxx.dat in the bitcoin

I'm writing a blockchain parser for bitcoin core with C++ and now I want to enrich the data I read with the raw transaction and the previous and next block hashes. I used this library to convert the ...
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1answer
30 views

How to get amount in RPC

I am developing a bitcoin wallet for education purposes, and i'm working on a getbalance method that given an address i return the balance of the address. Problem is, when communicating via the RPC ...
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1answer
557 views

Looking for code generate bitcoin address from passphase in C++

i'm try to write a program which generate bitcoin address from given hash sha256 of passphase as private key or given hex private key. I've found a library for this but it required Boost package in ...
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1answer
89 views

find a CTransaction from a prevout in Bitcoin source code

I'm trying to come up with this function: CTransaction getTxFromPrevout(COutPoint prevo); The idea being... when a new transaction is about to be validated, it will go through all of it's tx.vin[i]....
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1answer
133 views

bitcoin compile (.undefined reference to **')

I'm getting error after make command like, undefined reference to `BlockAssembler::BlockAssembler(CChainParams const&)' and in last Makefile:774: recipe for target 'all-recursive' failed make:...
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0answers
26 views

Failing to create a new address to be used for receiving staking rewards whenever a generated block is accepted

Our problem is that we need to get a new address on each stake. What I've tried so far is: Generating a new address right before a block is accepted and try using it to receive the stakes, but that ...
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1answer
118 views

Parse scripts to extract address [duplicate]

I want to parse a script with c++ to gain an output address from it. can anybody introduce a suitable library or a sample code which extract addresses from scripts ?
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1answer
293 views

How does bitcoin functional test framework work?

Could someone explain how and where in the code the bitcoin test framework calls map to C++ bitcoin core code or RPC calls such that regression suite tests the bitcoin core functionality? Background ...
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1answer
370 views

How can I create uncompressed public key in C++?

I need to derive public key from my private key in uncompressed form. I know how to create compressed one with libbitcoin, but I can't find appropriate method for uncompressed form there. Are there ...
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0answers
69 views

I'm trying to compile Bitcoin Gold but i'm still getting this error

In file included from ./addrman.h:14:0, from net.h:10, from miner.cpp:18: miner.cpp: In member function ‘std::unique_ptr BlockAssembler::CreateNewBlock(const CScript&,...
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1answer
2k views

Forking PIVX - ERROR: CheckBlockHeader() : proof of work failed

I have forked PIVX and generated new genesis block hash, merkle root and nonce, and changed the rewards parameters. It compiles fine and the daemon starts, I have even got 2 nodes connected, but ...
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2answers
256 views

C++ error building a fork of Bitcoin-ABC

I'm creating a Bitcoin-ABC based altcoin, everything was fine when I compiled dynamically for my Ubuntu machine, but when I try making a static release build I get: CXXLD libbitcoinconsensus.la ....
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2answers
483 views

Encountering “ReadBlockFromDisk: Errors in block header at CBlockDiskPos(nFile=0, nPos=8)” error when I ran modified litecoin chainparams.cpp

First: I am a newbite to altcoin development, next to generate an altcoin from litecoin, 1- I have made a clone of litecoin using git clone https://githubcom/litecoin-project/lotecoin.git 2- I changed ...
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1answer
700 views

How to debug bitcoin core in “real time”

I am new to bitcoin core and C++ I downloaded already the project from: https://github.com/bitcoin/bitcoin and run "makefile" command. Now I can make all transaction against the blockchain. I want ...
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2answers
479 views

Altcoin fork tutorial

Is there any tutorial for altcoin fork creation? I've found only tutorials for the very old versions, and any for the current ones.
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1answer
109 views

Where does the Bitcoin Core code serialize the number of transactions?

I've been studying the Bitcoin Core code, and I noticed that it uses a template READWRITE to serialize data structures for storing blocks. But it never seems to actually call "READWRITE(nTxs)", the ...
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1answer
288 views

A short program to mine a block

Anyone can give step-by-step explanation about the code below (if possible, with a c/c++ equivalent)? import hashlib, struct ver = 2 prev_block = "...
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2answers
473 views

What is most efficient way to validate bitcoin target (difficulty) value in C++

I have two values 1. h = hash of the block (32 bytes long in memory representation - not hex) 2. bits (uint32_t) To make the calculation easier we create a function difficulty such that: auto d = ...
1
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1answer
118 views

bitcoind json-rpc interface specification

Is there any document out there on the internet describing how access the json-rpc interface of the bitcoind daemon? In my case, my application is written with C++, and I want access this interface ...
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1answer
542 views

Question about retarget system bitcoin, add hardcodet block to exist blockchain

the standard values if (nActualTimespan < params.nPowTargetTimespan/4) nActualTimespan = params.nPowTargetTimespan/4; if (nActualTimespan > params.nPowTargetTimespan*4) ...
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0answers
147 views

G++ Trouble compiling litecoin on ubuntu server AMD64 (Version 16.04 Xenial)

I've been trying to compile litecoin for some time but keep getting an area that reads (/home/User/Downloads/Litecoin/src/leveldb/libleveldb.a: error adding symbols: Malformed archive collect2: error:...
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1answer
118 views

Been reading the bitcoin source code but unsure what this segment of Serialize.h does

I decided to learn about crypto (and C++) by first reading the entire C++ implementation of bitcoin. I'm having issue with this segment of serialize.h template<typename Stream, typename I> void ...
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0answers
268 views

make: *** No rule to make target 'all'. Stop. Stellar-core

I followed the instructions on how to install the stellar core but when I ran make install, I got this error: make: *** No rule to make target 'all'. Stop. I configured it and everything worked ...
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1answer
485 views

Simulator bitcoin miner

I was checking this C++ mining project to start with Bitcoin mining and understand better how mining works. This is the project: https://github.com/gavinandresen/bitcoin_miningsim But now i want to ...
4
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1answer
932 views

Transaction signature algorithm

As I know, standard ECDSA digital signature algorithm returns two values (according to this article or Wikipedia), but transaction push services or APIs, like this one, require one string as a ...
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2answers
2k views

C++ and secp256k1

I am working on a tiny C++ bitcoin application for a university project. I'm using Blockcypher API to create transactions, but I faced a problem with signing transaction's hash that returns one of the ...
20
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4answers
24k views

How to understand Bitcoin source code

I am not a C++ pro. I read C++ as a part of my undergrad school course. I am very passionate about the future currency i.e. Bitcoin. But I don't understand the source code structure. How to read the ...
2
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1answer
267 views

What is the function of LOCK(cs_main)?

Does LOCK(cs_main) pause and branach the program in order to do some necessary job before going on? I'm trying to publish blocks reactively (as a selfish miner) upon receipt of inventory message from ...
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1answer
179 views

How to access peer's tip of chain?

In case I'm a selfish miner and have successfully forked the blockchain, I'd like to know the state of progress of my honest nodes at any given time - how can I achieve this? Do peers on separate ...
2
votes
2answers
63 views

Two if's before sending an inventory message

Going through main.cpp I couldn't completely understand the purpose of a double barrier coded as if-statements: I'm referring to ... if (pto->setInventoryKnown.count(inv)) and if (pto->...
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1answer
253 views

Block Broadcasting - Unsolicited Block Push

Can someone, please, direct me to the source code section(s) relevant for an Unsolicited Block Push as described in the Bitcoin Developer Guide? I've been going through main.cpp and searched for the ...
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1answer
185 views

Call function for block n on blockchain

I've been going through main.cpp in order to roughly find out which function calls the best block and I found out depending on situation there are several similar-sounding function names and code ...
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1answer
158 views

“Array& params”: How to understand “&” after “Array” - type modifer?

I'm trying to understand how "invalidateblock"-function works, literally line by line. Since I'm at basic level in C++, I couldn't explain to myself what's the "&" after "Array" there to achieve ...
4
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1answer
696 views

Parameters in UpdateTip - calculation of log2_work

I looked up log2_work inside main.cpp and I can't follow its calculation by log(chainActive.Tip()->nChainWork.getdouble())/log(2.0). a) What is -> explicitely indicating? (I'm at basic level of ...
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1answer
229 views

How do I create release build of my new bitcoin wallet?

I have created a new alt coin, and now I want to create a executable of my wallet in ubuntu. I don't know how to create a release build wallet with all its dependencies. How I can build my wallet ...
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0answers
105 views

Bitcoin-qt doesn't get a server connection?

I have created a new altcoin, and I run a server on one machine and connect bitcoin-qt on another machine. In this case it's blink the network connection, sometimes it shows one connection and after ...
0
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1answer
311 views

How can I remove the charity features in my Devcoin clone?

I'm trying to produce a SHA256 altcoin which is merge mined with Bitcoin. I'd like to use some recent code, rather than base in on a 0.8.* or earlier codebase. I've found this source: https://github....
0
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1answer
156 views

Decode blocks received and Store in another file for analyzing

I am working on a bitcoin research project. I want to decode receiving blocks from the block chain and store decoded data in a separate file for analyzing purposes. For this purpose I digs the ...
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1answer
206 views

We need help with Reddcoin C++ - 1 btc bounty for solution [closed]

We need some help with Reddcoin. We had a bug in our code, 2 lines were commented so the verification of block we’re not done properly. https://github.com/reddcoin/reddcoin/commit/...
4
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2answers
2k views

How to interact with bitcoind using C++?

I know that bitcoind is written in C++, but I cannot figure out how to use its API within my program. I have been using a Python wrapper effectively, but I need another process running that is as ...
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1answer
2k views

Simple GPU C++ mining

I'm trying to mine a genesis block for an experimental Peercoin clone. I've already written one using boost threads, and it's been really fun since this is the most processor intensive program I've ...
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1answer
386 views

In the sourcecode, what does this line mean that recovers the key from the signature?

I understand that the public key (Q) can be extracted from a signature (r,s), but I'm having trouble understanding this line: if (!key.Recover(hash, &vchSig[1], (vchSig[0] - 27) & ~4)) The ...
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1answer
950 views

Simple GPU miner with long pooling C++

I want to write own GPU miner, but I can't find any simple solution (cgminer and RPC miner are big projects with many useless to me functions). I need the sources of only one GPU miner with long ...
4
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2answers
826 views

Is there bitcoin algorithms flowcharts or any other diagrams available?

To make those who not familiar with C++ to understand the algorithms.
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3answers
3k views

Can I send message inside the transactions script?

I would like to send transactions with messages as described in the wiki. In Transaction with slightly changed script is never relayed, someone answered that non-standard transactions are not relaid ...
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1answer
608 views

What is main.cpp for in bitcoind? [closed]

What does the main.cpp source-code file do? I know what main.cpp files are for in general, but specifically in the case of bitcoin?