The aim of Dart FFI project (tracked as Issue #34452) is to provide a low boilerplate, low ceremony & low overhead way of interoperating with native C/C++ code.
The motivation behind this project is twofold:
import 'dart:async'; | |
import 'package:flutter/material.dart'; | |
import 'dart:isolate'; | |
void main() => runApp(new MyApp()); | |
class MyApp extends StatelessWidget { | |
@override | |
Widget build(BuildContext context) { | |
return new MaterialApp( |
The aim of Dart FFI project (tracked as Issue #34452) is to provide a low boilerplate, low ceremony & low overhead way of interoperating with native C/C++ code.
The motivation behind this project is twofold:
A list of useful commands for the FFmpeg command line tool.
Download FFmpeg: https://www.ffmpeg.org/download.html
Full documentation: https://www.ffmpeg.org/ffmpeg.html
#!/bin/env python3 | |
import os | |
import mmap | |
import logging | |
import hashlib | |
import contextlib | |
log = logging.getLogger(__name__) | |
@contextlib.contextmanager | |
def directio_mmap(filename, readsize, offset): |
SPV clients lack the ability of full nodes to detect whether or not a chain provided to them by another source complies with the rules of the Bitcoin protocol.
SPV clients can connect to multiple full nodes in the hope that at least one of the nodes is honest and will provide them with the best valid chain, however situations may arise where the non-compliant chain contains more proof of work than the compliant chain. In this situation, there is no way for the honest full node to signal to an SPV client that it should disregard the chain with more proof of work.
Fraud proofs are a technique which provide honest full nodes the capability to conclusively demonstrate that chain is invalid regardless of the amount of proof of work backing the invalid chain.
If Bitcoin nodes implement the ability to create, propagate, and verify fraud proofs, the security of SPV clients will be improved.
(That's my attempt to understand what problem Impulse solves and how. I am not a designer/developer of this scheme.)
Regular Bitcoin transactions are not guaranteed until mined sufficiently deep in the blockchain. Unconfirmed transactions can be observed nearly instantly, but they cannot be trusted (could drop out because of insufficient fees, or double-spent).
Impulse Overview
#!/usr/bin/python3 | |
import requests, subprocess, time, smtplib | |
from email.mime.text import MIMEText | |
from bs4 import BeautifulSoup | |
class BitcoinPrice: | |
price = 0 | |
website = "http://www.bitcoinexchangerate.org/" |
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