## CppCon 2020 Template Metaprogramming: Type Traits Part 1 Jody Hagins jhagins@maystreet.com coachhagins@gmail.com ## CppCon 2020 Template Metaprogramming: Type Traits Introduction ## I ntended Audience oriented: shallow depth, slow current - Not necessarily beginner to C++, but beginner to traditional template metaprogramming techniques ## I ntended Audience • Beginner/Intermediate • Gentle entry: swimming oriented: shallow depth, slow current - Not necessarily beginner to C++, but beginner to traditional template metaprogramming techniques • Type traits part of standard library for ~10 years ## I ntended Audience

## Template-Less MetaProgramming 0 ## +24 ## KRIS JUSIAK 2024 September 15 - 20 ## Template Metaprogramming (TMP) template using meta_fun = this_talk; ## static_assert(Template::Metaprogramming::is_hard); // ✓ ?static_assert(Template::Metaprogramming::is_hard); // ✓ ?static_assert(Template::Metaprogramming::is_powerful); // ✓ ?static_assert(Template::Metapr // ✓ ?static_assert(Template::Metaprogramming::is_powerful); // ✓ ?static_assert(( Template::Metaprogramming::is_easy and Template::Metaprogramming::is_powerful and Template::Metaprogramming::has

### Named Optional Parameters - JavaScript Style Brian Davidson (briandavidson@meta.com) ## Summary C++ developers often run into the situation where we have multiple parameters in a function with the function arguments forming a clear function call ## I nspiration: Javascript The anonymous object parameters of javascript provide a readable function API. logger({one:0.9999}); > 0.9999 logger({one:"one"

## V ariadic templates: Parameter pack ## ■ Syntax: A typename|class... Ts generates a type template parameter pack with optional name. B Args... ts a function argument parameter pack with optional D ts... in the body of a function to unpack the arguments. 1 templatetemplate="" 4="" constexpr="" auto="" 5="" min(const="" t&="" a,="" const="" C++11, there are variadic templates: Variadic templates are templates that take any number of parameters. - Already known by variadic macros or variadic functions. 1 Helper functions to convert everything

instantiation for a new type or value results in additional code, the fill-in template is generated with the given template argument. Templates reduce a lot of writers' work. We do not have to implement Templates are always initiated by the keyword template. ## The different kinds of template parameters There are three different types of template parameters: Type parameter whenever we use a concrete type type, e.g., int, char, or even a class. Type parameters are the most common type. none-type parameter typically values like 3. Excluded are floating-point numbers and strings (C-arrays). Since C++20,

• Write views that actually do something • Raising a 404 error • Use the template system • Removing hardcoded URLs in templates • Namespacing URL names classes Working with form templates Further topics Templates - The Django template language - Support for template engines Class-based views - Introduction to class-based views - Built-in Django's cache framework - Setting up the cache - The per-site cache - The per-view cache - Template fragment caching - The low-level cache API - Asynchronous support - Downstream caches - Using

New host 126 3 New item 128 4 New trigger 129 5 Receiving problem notification 131 6 New template 135 6 Zabbix appliance 137 7 Configuration 140 1 Hosts and host groups 149 2 Items 159 4 Events 347 5 Event correlation 350 6 Tagging 357 7 Visualization 360 8 Templates and template groups 387 9 Templates out of the box 388 10 Notifications upon events 397 11 Macros 442 Problem acknowledgment 544 1 Problem suppression 546 14 Configuration export/import 547 1 Template groups 549 2 Host groups 549 3 Templates 549 4 Hosts 569 5 Network maps 587 6 Media types

packages 69 5 Installation from containers 87 6 Upgrade procedure 93 7 Known issues 102 8 Template changes 104 9 Upgrade notes for 4.4.0 105 10 Upgrade notes for 4.4.1 106 11 Upgrade notes 112 3 New item 113 4 New trigger 116 5 Receiving problem notification 118 6 New template 122 6. Zabbix appliance 124 7. Configuration 127 1 Hosts and host groups 133 674 2 User profile 773 3 Global search 777 4 Frontend maintenance mode 779 5 Page parameters 780 6 Definitions 781 7 Creating your own theme 782 8 Debug mode 783 9 Cookies

josuttis.com 3 josuttis | eckstein IT communication ## Generic Function to Insert a Value C++98 template void add(CollT& coll, const T& val) { coll.push_back(val); me> Overloading Function Templates template void add(CollT& coll, const T& val) { coll.push_back(val); } template communication Constraints with Concepts C++20 template concept HasPushBack = requires (CollT c, CollT::value_type v) { c.push_back(v); }; template requires

from packages 58 4 Installation from sources 60 5 Upgrade procedure 68 6 Known issues 69 7 Template changes 70 8 Upgrade notes for 2.2.0 71 9 Upgrade notes for 2.2.1 75 10 Upgrade notes for 3 New item ..... 85 4 New trigger ..... 87 5 Receiving problem notification ..... 88 6 New template ..... 91 5. Zabbix appliance ..... 93 6. Configuration ..... 97 1 Hosts and host groups . User profile ..... 406 3 Global search ..... 410 4 Frontend maintenance mode ..... 412 5 Page parameters ..... 413 6 Definitions ..... 413 7 Creating your own theme ..... 415 8 Debug mode .....