designed ones!When talking about performance, we typically think about the function logic. We’ll see that a well designed function API can have an even larger impact.How will we compare performance? ● they might be, and often are, totally irrelevant to speed. 17 Credit to Khalil Estell: Firefox function distribution 157946 functions above (127B) 167404 functions below (127B)Understanding how machine problems? Pros: ● Default constructor before the function call is avoided 36Does it solve our problems? Pros: ● Default constructor before the function call is avoided Cons (unless we fully trust the

Back to Basics - Function Call Resolution Copyright © 2024 by Ben Saks and Dan Saks Back to Basics: Function Call Resolution by Ben Saks and Dan Saks September, 2024 1 Saks & Associates These notes +1-412-521-4117 (voice) service@saksandassociates.com saksandassociates.com 2Back to Basics - Function Call Resolution Copyright © 2024 by Ben Saks and Dan Saks About Ben Saks Ben Saks is the chief Ben earned a B.A. with Distinction in Computer Science from Carleton College. 4Back to Basics - Function Call Resolution Copyright © 2024 by Ben Saks and Dan Saks About Dan Saks Dan Saks is the president

Limitations and Problems in std::function and similar constructs Amandeep Chawla | Sr. Computer Scientist II amandeep@adobe.com | adchawla@gmail.com Image by Bruno Tornielli© 2024 Adobe. All Rights we can control. ▪ std::function© 2024 Adobe. All Rights Reserved. Adobe Confidential. Task Based Mechanism© 2024 Adobe. All Rights Reserved. Adobe Confidential. std::function ▪ Is a class template ▪ It is a general-purpose polymorphic function wrapper ▪ Instances of std::function can store, copy, and invoke any CopyConstructible Callable target ▪ Uses type-erasure under the hood to gain all the

SFINAE Overload Resolution (Viable) Candidate Functions Ranking Ambiguous Function Calls Access Labels Function Template Specializations Virtual Dispatch Deleting FunctionsContent 4 Overview SFINAE Overload Resolution (Viable) Candidate Functions Ranking Ambiguous Function Calls Access Labels Function Template Specializations Virtual Dispatch Deleting FunctionsDisclaimer 5 This Argument Deduction Name Lookup Template Argument Deduction For all candidate function templates, deduce all function template parameters based on the given template arguments. and add them to the

Conditional function body constexpr everything Disable Cuda warnings host device template 3 The dark path Function dispatch triple 4 Cuda proposal Conditional host device Forbid bad cross function calls Cuda proposal Thank you Allowed function calls in Cuda CPU host GPU global device9/66 Motivation Patterns The dark path Cuda proposal Thank you Allowed function calls in Cuda CPU host GPU global Quiz time12/66 Motivation Patterns The dark path Cuda proposal Thank you Quiz time: Bad cross function calls � � 1 struct H { __host__ int func() { return 42; } }; 2 3 struct D { __device__ int func()

○ N = number of checked function calls 86My Hypothesis ● Cost of using result types: S(N) = aN ○ a = average cost of a check per call ○ N = number of checked function calls ● Cost of using exception: using result types: S(N) = aN ○ a = average cost of a check per call ○ N = number of checked function calls ● Cost of using exception: S(M) = bM + E ○ b = average cost of exception metadata ○ M = number Functions ❌ Calls other functions ❌ Contains destructors ❌ try/catchThe 3 types of functions 100 ������ Leaf Functions ������ Transparent-Trivial Functions ������ Reentrant Functions ❌ Calls other functions

(w: w.index() == i); // postcondition assertion Proposal: add contract assertions to C++ Function contract assertions5 Copyright (c) Timur Doumler | @timur_audio | https://timur.audio arguments and/or program state when a function is called. Obligation of caller (client) postcondition = Condition on return value and/or program state when a function returns. Obligation of callee (implementer)30 audio • Precondition assertions (pre): after the initialisation of function parameters, before the evaluation of the function body • Postcondition assertions (post): after the result object value

Matcher Reference 56AST Matchers - Matcher Expressions Looking for calls to a member function on a class named A and whose called function is named foo and whose first parameter is an integer. 57 cxxMemberCallExpr( hasType(isInteger())))))AST Matchers - Matcher Expressions Looking for calls to a member function on a class named A and whose called function is named foo and whose first parameter is an integer. 58 cxxMemberCallExpr( hasType(isInteger())))))AST Matchers - Matcher Expressions Looking for calls to a member function on a class named A and whose called function is named foo and whose first parameter is an integer. 59 cxxMemberCallExpr(

com 3 C++ Concepts, Constraints, and Requirements C++20 ©2024 by josuttis.com 4 C++ Generic Function to Insert a Value template void add(CollT& coll, const T& val) { coll C++98 Nico Josuttis C++ Concepts @cppcon 2024-09-18 2©2024 by josuttis.com 5 C++ Overloading Function Templates template void add(CollT& coll, const T& val) { coll.push_back(val); std::set coll2; add(coll1, 42); add(coll2, 42); Overload resolution prefers more specialized function C++20 Constraints formulated by a requires clause Requirements with requires expression Concept

functions! We'll start with a basic function example, identifying the function signature and basic abilities of a function. Then we are going to view this function again from the perspective of assembly assembly (using compiler explorer) to show you how a function is structured. From the assembly view, we will then observe that functions have addresses (they must after all!) and that we can store functions pointers. We'll take a brief aside to show you how modern C++ also gives us the convenient std::function. Functions need not always be 'global' building blocks of our programs, the next step in our journey