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

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();

composing functions. Jonathan Müller — @foonathan Back to Basics: Functional Programming in C++ CppCon 2024-09-19 4Functional Programming Definition Declarative programming by composing functions. fac C++ CppCon 2024-09-19 4Functional Programming Definition Declarative programming by composing functions. fac :: Int -> Int fac 0 = 1 fac n = n * fac (n - 1) sort :: [Int] -> [Int] sort [] = [] sort CppCon 2024-09-19 6Functional programming in C++ Definition Declarative programming by composing functions. Jonathan Müller — @foonathan Back to Basics: Functional Programming in C++ CppCon 2024-09-19 7Functional

UsageBack to Class! 151617 Consider the output pin Microcontroller18 Consider the output pin Microcontroller pins Microcontroller19 Consider the output pin Microcontroller Pin resistor LOW = ~0V time voltage20 Consider the output pin Microcontroller Pin resistor HIGH = ~3.3V time voltage electrical currentclass output_pin { public: virtual ~output_pin() = default; virtual void void level(bool p_high) = 0; }; 2122 class output_pin { public: virtual ~output_pin() = default; virtual void level(bool p_high) = 0; }; Is returning void okay?I2C Bus Controller SDA SCL I2C

inextricably linked to the ROS 2 API ● set_map_service and generate_path_service are callback functions that run when requests are sent via the ROS 2 middlewareConventional Approach class PathGenerator are callback functions that run when requests are sent via the ROS 2 middleware ● Those functions call the set_costmap and generate_global_path functions, which are private functions that contain are callback functions that run when requests are sent via the ROS 2 middleware ● Those functions call the set_costmap and generate_global_path functions, which are private functions that contain

runtime. The emergence of Lambda expressions has given C++ the “closure” feature of “anonymous functions”, which are in almost all modern programming languages (such as Python, Swift, etc). It has become \n"; }(); return 0; } You should first compile the C code with gcc: gcc -c foo.c Compile and output the foo.o file, and link the C++ code to the .o file using clang++ (or both compile to .o and then When we declare, define a variable or constant, and control the flow of code, object-oriented functions, template programming, etc., before the runtime, it may happen when writing code or compiler compiling

enough functions” 5Tony Van Eerd: “people are not writing enough functions” 6Tony Van Eerd: “people are not writing enough functions” 7Tony Van Eerd: “people are not writing enough functions” 8When 8When people finally start writing more functions, we’d prefer to get only the well designed ones!When talking about performance, we typically think about the function logic. We’ll see that a well designed for non-inlined functionsISO C++ wiki: Do inline functions improve performance? Yes and no. Sometimes. Maybe. There are no simple answers. inline functions might make the code faster, they might make it