Calling Functions A Tutorial Klaus Iglberger, CppCon 2020 klaus.iglberger@gmx.de2 Klaus Iglberger C++ Trainer since 2016 Author of the C++ math library (Co-)Organizer of the Munich Two-Phase Lookup Template Argument Deduction SFINAE Overload Resolution (Viable) Candidate Functions Ranking Ambiguous Function Calls Access Labels Function Template Specializations Virtual Two-Phase Lookup Template Argument Deduction SFINAE Overload Resolution (Viable) Candidate Functions Ranking Ambiguous Function Calls Access Labels Function Template Specializations Virtual

for many years -- please provide suggestions, analogies, and other useful ways to think about functions now or in the future!Please do not redistribute slides without prior permission. 4Your Tour Guide for the talk ● Located here: https://github.com/MikeShah/Talks/tree/main/2023/cppcon/functions 6Abstract Functions are one of the first things programmers learn, granting you the ultimate power to 'reuse' overview of functions from the start to the end, on the various powers that are given to us from the ground up. Consider this talk your one stop for learning all of the great things about functions! We'll

From Functions to Coroutines 40 Years Evolution Rainer Grimm Training, Coaching, and Technology Consulting www.ModernesCpp.netEvolution of Callable template T invoke(Func sequence of functions can be changed ▪ Automatically parallelizable ▪ Results can be cachedPure Functions Working with a pure function is based on discipline Use common functions, meta-functions, constexpr constexpr, or consteval functions ▪ Function int powFunc(int m, int n){ if (n == 0) return 1; return m * powFunc(m, n - 1); } ▪ Meta-Function template struct PowMeta { static int const value

C++20 ❤ SQL John R Bandela, MDOverview u SQL u C++ Example u Implementation techniques u fixed_string u meta_struct u Parsing compile time strings into meta_structsOverview v SQL v C++ Example {price_from_user};Avoiding SQL Injection Attacks SELECT orders.id, name, item, price, discount_code FROM orders JOIN customers ON customers.id = customerid WHERE price > ?;SQL Library Options u Traditional Lots of information available u Vulnerable to sql injection of developer not careful u Use dynamic typingDomain Specific Language u Use types to encode SQL u Looks more like regular C++ u Typically requires

virt_duration = end-start;There are interesting technical details and surprising conclusions that virtual functions can be actually faster. Since CPU architectures are mentioned, I'd expect to see deep assembly eritance-vs-other- ways-performanceDoes it even matter?Conclusions ● The notion that “virtual functions are slower” is flat out wrong. ○ Which is not to say they are faster ○ Some of the suggested

Helmut Hlavacs – Combining Co-Routines and Functions into a Job System - CppCon 2021 1 / 39Helmut Hlavacs – Combining Co-Routines and Functions into a Job System - CppCon 2021 2 / 39 About Myself • Professor Processing) Technical Committee 14 Entertainment ComputingHelmut Hlavacs – Combining Co-Routines and Functions into a Job System - CppCon 2021 3 / 39 Creating Game Engines with C++ • Vienna Game Job System Vulkan Game Engine 2.0 https://github.com/hlavacs 20Helmut Hlavacs – Combining Co-Routines and Functions into a Job System - CppCon 2021 4 / 39 The Game Loop auto prev = high_resolution_clock::now();

onTrap); setHandler(SIGALRM, onTimer); setHandler(SIGSEGV, onFault); for(Function* f: functions) { f->setTrap(); } setTimer(interval); int r = stabilizer_main(argc, argv); onTrap); setHandler(SIGALRM, onTimer); setHandler(SIGSEGV, onFault); for(Function* f: functions) { f->setTrap(); } setTimer(interval); int r = stabilizer_main(argc, argv); onTrap); setHandler(SIGALRM, onTimer); setHandler(SIGSEGV, onFault); for(Function* f: functions) { f->setTrap(); } setTimer(interval); int r = stabilizer_main(argc, argv);

• API • Design • Implementation details • Using compile-time parsers • Reflection • Examples: functions, types, treesParser In a compiler: tokens -> parser -> syntax tree In a web browser: text -> sizeof(arr[0])); vector v = {1,2,3,4};Operator Overloading Use operators to call custom functions for specific types. std::filesystem::path p = "C:"; return p / "files" / "images" / "cat.png"; language tailored to solve problems within a specific domain or application context. Examples: • SQL • CSS • Regular Expressions (PCRE) • Make (makefile)DSL Example – Boost Spirit Boost Spirit library

break-ins • Spies (insider attacks) • Spear phishing • Door rattling • Denial of service attacks • SQL injection • Corrupted input/Data • Rule of thumb: always first attack the weakest link Stroustrup later) • From my 1979 lab book: • A “new function” creates the run-time environment for member functions • A “delete function” reverses that • Later (1983) • “new function” -> constructor • “delete function” File_error(s,r); } ~File_handle() { fclose(p); } // destructor // copy operations // access functions }; void f(string s) { File_handle fh {s, "r“}; // now: ifstream fh{s} // use fh }

IntelliSense across your files Download the Extension of Your Choice: Jupyter Notebooks • Use C#, Python, SQL, PowerShell, and more in one notebook • Invoke executable scripts What if I’m working with multiple experience: • Extract function/Member function • Signature Editing • Generating overrides for virtual functions • Add Missing Includes to File Performance Improvements • (IntelliSense generation, etc.) aka