James Blackburn jimbob88

ELF Format Cheatsheet

Introduction

Executable and Linkable Format (ELF), is the default binary format on Linux-based systems.

Compilation

An Example of Linux Kernel Module using GPIO Subsystem

This is a kernel module, with DT Overlay, to illustrate usage of GPIO subsystem in Linux kernel.

Hardware Envoronment

Raspberry Pi 3 Model B Rev 1.2
Arduino UNO

Software Environment

`.run()` is bad for libraries

As a developer I have noticed a trend in libraries where the library developer will write this amazing library that does everything you need it to except that it has a .run() or .start() method. The intent is for the user of said library to do the initialization code in the application entry point and then do something like return app.run();. Whether it's in Python, Java, C++, or Rust they all abstratct away the application's main event loop.

What is an event loop?

React recently introduced an experimental profiler API. This page gives instructions on how to use this API in a production release of your app.

Table of Contents

Profiling in production
- Create React App
- Webpack 4

Profiling in production

React DOM automatically supports profiling in development mode for v16.5+, but since profiling adds some small additional overhead it is opt-in for production mode. This gist explains how to opt-in.

	// you need this in your cargo.toml
	// reqwest = { version = "0.11.3", features = ["stream"] }
	// futures-util = "0.3.14"
	// indicatif = "0.15.0"
	use std::cmp::min;
	use std::fs::File;
	use std::io::Write;

	use reqwest::Client;
	use indicatif::{ProgressBar, ProgressStyle};

	<!DOCTYPE html>
	<html lang="en">

	<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">

	<title>Canvas</title>

	#include <iostream>
	#include <string>
	#include <queue>
	#include <unordered_map>
	using namespace std;

	// A Tree node
	struct Node
	{
	char ch;

	/// Multi-level sort a slice of Foobars according to [(field, reverse)]
	fn sort_by_names(f: &mut [Foobar], orderings: &[(Foofields, bool)]) {
	use std::cmp::Ordering;

	f.sort_by(\|a, b\| {
	let mut cmp = Ordering::Equal;
	for (field, reverse) in orderings {
	if cmp != Ordering::Equal {
	break;
	}

	import React from "react"
	class Form extends React.Component {
	state = {
	cats: [{name:"", age:""}],
	owner: "",
	description: ""
	}
	handleChange = (e) => {
	if (["name", "age"].includes(e.target.className) ) {
	let cats = [...this.state.cats]

	$path = $args[0]

	Add-Type -AssemblyName PresentationFramework
	[System.Windows.MessageBox]::Show("Hello $path")