This gist will no longer be updated as the changelog will be on the official website.
Converted via https://domchristie.github.io/turndown
Here's a list of mildly interesting things about the C language that I learned mostly by consuming Clang's ASTs. Although surprises are getting sparser, I might continue to update this document over time.
There are many more mildly interesting features of C++, but the language is literally known for being weird, whereas C is usually considered smaller and simpler, so this is (almost) only about C.
struct foo {
struct bar {
int x;
| import UIKit | |
| /// A validation rule for text input. | |
| public enum TextValidationRule { | |
| /// Any input is valid, including an empty string. | |
| case noRestriction | |
| /// The input must not be empty. | |
| case nonEmpty | |
| /// The enitre input must match a regular expression. A matching substring is not enough. | |
| case regularExpression(NSRegularExpression) |
| import XCTest | |
| let count = 50000 | |
| class StringsTestTests: XCTestCase { | |
| // MARK: Copying | |
| func testInterpolation() { | |
| var foo = "" |
What is strict aliasing? First we will describe what is aliasing and then we can learn what being strict about it means.
In C and C++ aliasing has to do with what expression types we are allowed to access stored values through. In both C and C++ the standard specifies which expression types are allowed to alias which types. The compiler and optimizer are allowed to assume we follow the aliasing rules strictly, hence the term strict aliasing rule. If we attempt to access a value using a type not allowed it is classified as undefined behavior(UB). Once we have undefined behavior all bets are off, the results of our program are no longer reliable.
Unfortunately with strict aliasing violations, we will often obtain the results we expect, leaving the possibility the a future version of a compiler with a new optimization will break code we th
| import Foundation | |
| /// Writes a canonical hex+ASCII representation of `bytes` into `output`. | |
| func hexdump<Target>(_ bytes: UnsafeRawBufferPointer, to output: inout Target) | |
| where Target: TextOutputStream | |
| { | |
| guard bytes.count > 0 else { return } | |
| var asciiString = "" |
| // UICollectionView Objective-C example | |
| - (void)viewWillAppear:(BOOL)animated { | |
| [super viewWillAppear:animated]; | |
| NSIndexPath *selectedIndexPath = [[self.collectionView indexPathsForSelectedItems] firstObject]; | |
| if (selectedIndexPath != nil) { | |
| id<UIViewControllerTransitionCoordinator> coordinator = self.transitionCoordinator; | |
| if (coordinator != nil) { | |
| [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) { |
For a brief user-level introduction to CMake, watch C++ Weekly, Episode 78, Intro to CMake by Jason Turner. LLVM’s CMake Primer provides a good high-level introduction to the CMake syntax. Go read it now.
After that, watch Mathieu Ropert’s CppCon 2017 talk Using Modern CMake Patterns to Enforce a Good Modular Design (slides). It provides a thorough explanation of what modern CMake is and why it is so much better than “old school” CMake. The modular design ideas in this talk are based on the book [Large-Scale C++ Software Design](https://www.amazon.de/Large-Scale-Soft
| #!/usr/bin/env ruby | |
| require 'optparse' | |
| require 'pathname' | |
| require 'open3' | |
| # This tool checks an input path for all static libraries *.a files | |
| # and makes sure they were built with the most modern ObjC ABI version. | |
| # Parse command line options. |
In this article we compared different behavior of static, inline and static inline free functions in compiled binary.
All the following test was done under g++ 7.1.1 on Linux amd64, ELF64.
#pragma once
inline int only_inline() { return 42; }
static int only_static() { return 42; }