Bill Hoffman, CTO @ Kitware creator of CMake 1 import CMake; // Mastering C++ Modules2 _____________________ GUY CMake / Sandal / Kitware Bill Hoffman3 About Me • 1990-1999 GE research in a Computer // Mastering C++ ModulesEnough with the Background Let's Talk Modules! 7C++ Named Modules Only 8 See Daniel Ruoso talk: "C++ Modules: The Challenges of Implementing Header Units" From C++ Now 20239 -std:c++20 -interface -c A.cpp A.cpp $ ls A.cpp A.ifc A.obj B.cpp B.ifc B.objChicken and the Egg • Modules require the build system to know which files produce which BMI files and which files consume them

1Daniela Engert - CppCon 2021 Modules demystified and applied A (SHORT) TOUR OF C++ MODULES 2ABOUT ME Electrical engineer Build computers and create software for 40 years Develop hardware and 30 years Member of the C++ committee (learning novice) employed by 3OVERVIEW Modules Foundations C++20 Modules, a short recap Module unit types and Module composition Visibility of Identifiers linkage and linker symbols Modules in practice Moving towards modules (by example) Imports are different! Is it worth it? (a case study) The state of the ecosystem 4C++20 MODULES a short recap 5source

1/50 C++ Modules - Getting Started Today Andreas Weis Woven by Toyota CppCon 20232/50 Introduction3/50 About me - Andreas Weis (he/him) ComicSansMS Co-organizer of the Munich C++ User Group Currently // [...]10/50 Hello Modules! — File: module.cpp export module my_module; export char const* my_function () { return "Hello Modules!"; } — File: main.cpp #include import S{}; }16/50 Daniela Engert - The three secret spices of C++ Modules - Visibility, Reachability, Linkage17/50 Different shapes of modules18/50 Primary Module Interface Unit — File: my module.cpp export

C++20 Modules: The Packaging and Binary Redistribution StoryScope ● Brief introduction on C++ modules and their advantages ● Focus on named modules ● Using modules today ○ Can we package module-ready world!\n"); }Why use modules In short: better isolation - some advantages to headers: ● Importers cannot affect the contents of the module being imported ● Imported modules cannot affect the state Ordering of imports does not matter ● Potential for improved build times (more on this later)Why use modules (cont’d) wirepair.org C:\path\to\include\fb/verifier.h(38,23): warning C4003: not enough arguments

Implementing C++ Modules: Lessons Learned, Lessons Abandoned Gabriel Dos Reis & Cameron DaCamara MicrosoftOverview 2 (C) Dos Reis & DaCamara; CppCon 2021C++ Modules Design Goals 1. Componentization Named modules provide ODR guarantees, by design – Header files and header units require (expensive) incomplete ODR checks, and demand complete trust 4 (C) Dos Reis & DaCamara; CppCon 2021Modules and ODR hunt” (C) Dos Reis & DaCamara; CppCon 2021 6The Global Module ▪ Everything we used to do before Modules – Merry mess ▪ Provide no ODR guarantees – Responsibility of the programmer ▪ Complete ODR check

systems which use CMake ○ C++ modules support ● Working with the community to improve building software ○ ISO standards ■ Dependency format ○ Pushing forward modules support in other build systems systems ■ xmake ■ bazel 2Outline 1. What are compilation databases? 2. How do modules change the status quo? 3. Build databases 3Compilation Databases: Overview ● JSON document ● Array of JSON objects files) ● C++ modules… Compilation Databases: Limitations 2 9C++ Modules on the Scene ● Modules complicate C++ compilation ○ Surprise! 🎉 ○ Basically inherit the Fortran 90 modules compilation model

Building a central Go modules repository: GoCenter’s back to the future. @jfrog @ankushchadha111 GopherCon 2019 Lightning Talk Ankush Chadha About me • Dev Manager, Community & Partner Engineering @ankushchadha111 We Golang @jfrog @ankushchadha111 go modules @jfrog @ankushchadha111 reproducible builds @jfrog @ankushchadha111 Use go modules correctly @jfrog @ankushchadha111 @jfrog @ankushchadha111 Projects that adopted go modules @jfrog @ankushchadha111 @jfrog @ankushchadha111 Projects that haven’t adopted go modules yet @jfrog @ankushchadha111 go mod init

Why do I care about reflection even more?• Implement reflection • Go over current techniques • Modules • Patterns and Tricks for runtime reflection 9 How do we get there?• Go from client API 1 0 put in source C++ compilation process• “Modules are a tooling opportunity” - Gabriel dos Reis • Fast! Work already happened 2 4 What happens with modules?2 5 • No further context needed • In theory add_executable(TheExe) target_link_libraries(TheExe PUBLIC MyProject MyProject_ReflectionData )• Only modules • No user attributes • BMI filename query 3 1 Trivial Ifc limitations• Templates not instantiated

Apache License, Version 2.0 许可证. 模块 | 指令 | 常见问题 | 术语 | 网站导航 其它主题 常见问题 网站导航 开发文档 其它说明 维基 Modules | Directives | FAQ | Glossary | Sitemap Apache HTTP Server Version 2.4 Apache > HTTP Server > Documentation used in most cases. There are some changes in the default settings. Some details of changes: These modules have been removed: mod_authn_default, mod_authz_default, mod_mem_cache. If you were using mod_mem_cache These were believed to be broken anyway. configure: dynamic modules (DSO) are built by default configure: By default, only a basic set of modules is loaded. The other LoadModule directives are commented out

Apache License, Version 2.0 许可证. 模块 | 指令 | 常见问题 | 术语 | 网站导航 其它主题 常见问题 网站导航 开发文档 其它说明 维基 Modules | Directives | FAQ | Glossary | Sitemap Apache HTTP Server Version 2.4 Apache > HTTP Server > Documentation used in most cases. There are some changes in the default settings. Some details of changes: These modules have been removed: mod_authn_default, mod_authz_default, mod_mem_cache. If you were using mod_mem_cache These were believed to be broken anyway. configure: dynamic modules (DSO) are built by default configure: By default, only a basic set of modules is loaded. The other LoadModule directives are commented out