Agenda  Compile-Time Rational Numbers  Durations  Clocks  Time Points  Dates  Time Zones 4 Agenda  Compile-Time Rational Numbers  Durations  Clocks  Time Points  Dates Dates  Time Zones5 Compile-Time Rational Numbers  Defined in  Work with rational numbers at compile time  Always normalized representation  Needed for durations in the library6 library6 Compile-Time Rational Numbers  Define a rational number: using r1 = ratio<1, 60>; // Represents 1/60  Retrieve numerator and denominator intmax_t num { r1::num }; intmax_t den { r1::den };

More Tests Production Detecting errors early in the development pipeline reduces costs, saves time, minimizes risk, and improves efficiency.Error Reporting - Goals Error messages should be clear, risks if used improperlyCompile-time Validation CompilerMech Suit or Swim? Choose between safety and flexibilityMech Suit that Swims Safety and flexibility at the same time Source: Gurren LaganRuntime report_error(error); } }Runtime Error Reporting Runtime error reporting can be used with compile-time error detection void foo(){ constexpr auto error = detect_error(); if constexpr (error) {

in game jams. • Enjoy experimenting, exploring, and trying new things in C++.Dive Into Compile-Time Parsers Libraries Use Cases Implementation Techniques Reflection Language Evolution API Design overloading • Domain specific languages • Open source compile-time libraries • API • Design • Implementation details • Using compile-time parsers • Reflection • Examples: functions, types, treesParser parser("SELECT id, name WHERE age > 42"); std::vector result = func(cats);Example – Compile Time Parsers std::vector cats = { /*...*/ }; constexpr auto parser = create_parser(); constexpr

Stephen Brawner, Robottimo Robotics at Compile Time Optimizing Robotics Algorithms with c++’s Compile-Time FeaturesAbout me • Robotics Software Consultant based in Portland, OR • Chief Roboticist types of robots • Parses robot description from a plain-text file format • Requires lots of run-time decisions • Generally maintained by a corporate entity • ROS and ROS 2 ecosystem (Open Robotics/ platforms in mind • Generally required for real-time controls• video of FLX BOTRobotics Hardware Development • Requirements known well ahead of time • Mechanical and electrical designs are locked-in

CPPCON / 16TH SEPTEMBER 2020 CPPCON / 16TH SEPTEMBER 2020 JUST-IN-TIME COMPILATION: JUST-IN-TIME COMPILATION: THE NEXT BIG THING? THE NEXT BIG THING? BEN DEANE & KRIS JUSIAK - BEN DEANE & KRIS JUSIAK 3 . 2WHAT IS JITTING? WHAT IS JITTING? INSTEAD OF AHEAD-OF-TIME (AOT), AKA "THE NORM": IT'S LIKE THE APPLICATION INSTEAD OF AHEAD-OF-TIME (AOT), AKA "THE NORM": IT'S LIKE THE APPLICATION (/LIBRARY) IS 3 . 2WHAT IS JITTING? WHAT IS JITTING? INSTEAD OF AHEAD-OF-TIME (AOT), AKA "THE NORM": IT'S LIKE THE APPLICATION INSTEAD OF AHEAD-OF-TIME (AOT), AKA "THE NORM": IT'S LIKE THE APPLICATION (/LIBRARY) IS

Just-in-Time Compilation A lecture on the last 60 years JF Bastien Software architect @jfbastien Presented at CppCon 2020. Just-in-Time compilers... we've all heard of them! What are they really want them, are they actually a good idea, and how do they fit in with C++ since we all use Ahead-of-Time compilers? In this talk I'll tell you about C++ AoT compiler, JiTs for dynamic language, JiTs for compilers. I'll illustrate how our view of compilers is really monolithic, and how compilers through time, and still today, are actually a continuum.Papers in this talk github.com/jfbastien/jit-talk CppCon

1/ Introduction Explore how C++20's constexper features can: Generate data from code at compile-time Be used to construct: Lookup Tables Con�guration Fuses Compressed Strings USB Descriptors 2 . 1/ building compile-time libraries 2 . 2/ constexpr in Brief Speci�es a variable or function CAN appear in a constant expression Constant expressions can be evaluated at compile-time eg: Array size non-type produce a compile-time constant Implies constexpr 4/ constinit Speci�es a variable has static initialization constant initialised (from a constant expression) computed at compile-time, and stored in

Gela Malek Pour gmalekpour@esri.com Visualize Time Enabled Data using ArcGIS Qt (C++) and ToolkitAbout Esri • We build mapping technology that our customers use to solve the world’s most complex challenges around the worldPurpose of this talk • Showcase a quick way to create a desktop app to visualize time enabled data • Setup the development environment using Esri templates • Use the ArcGIS toolkit to feature layer that include hurricane data as features • Each feature has a specific start time and end time in the feature table • We will use these start and end date values to draw and clear features

AI, Inc. Errors have a high cost, so rigorous testing is a must We use increasingly more compile-time polymorphism and checks Question: how to test if something is compilable in a rigorous way? We use std::enable_if_t< std::is_floating_point_v>© 2021 Apex.AI, Inc. Code has a tendency to evolve with time template< class T, class = std::enable_if_t>> T get_half_of(T smth) return smth / T{2}; } image: Flaticon.com© 2021 Apex.AI, Inc. Code has a tendency to evolve with time template< class T, class = std::enable_if_t>> T get_half_of(T smth)

a wave digital voltage source, resistor, and capacitor, all connected with a series adaptor. Real-Time Circuit Simulation with Wave Digital Filters in C++ Author: Jatin Chowdhury Affiliation: Chowdhury simulations of analog circuits as part of their sound-processing algorithms. Given that audio effects are typically required to run in “real-time”, traditional circuit modelling softwares (e.g. LTSpice) allowing the user to quickly and easily construct circuit simulations that are suitable for real-time applications. Wave Digital Filters Wave Variables Wave Digital Filters (WDFs) use “wave variables”