A Practical Introduction to C++20's Modules

on YouTube ↗01h 11m

" summary

Practical walk-through of C++20 modules using Visual Studio 16.8/16.9 shows how to write .ixx module interface units, separate implementation units, and import the standard library via header units (standard library guaranteed); demo compiles and runs, and fmt worked as a header unit in the demo. Highlights: macros become module-local, non-exported symbols get module linkage, and name collisions in the global namespace can make the program ill-formed, no diagnostic required; MSBuild support is good, GCC/Clang are partial and CMake lacks official support.

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" chapters (15)

1. 0:00VIRTUAL EVENT A Practical Introduction to C++20's Modules
2. 3:41Modular Programming Modules separate a program into independent and interchangeable units • Modules hide the actual implementation and possibly data and • A module is not a package
3. 29:48Module Names A number of identifiers joined by does
4. 31:31Modules and Namespaces
5. 34:34Module Partitions
6. 36:44Private Module Fragment • Keep interface and implementation separate without having multiple files • modification of the private module fragment cannot trigger recompilation of importers of the module • Possibly faster incremental buids
7. 40:23Global Module Everything must be attached to a module declared in a module
8. 41:12What Can Be Exported? variables classes, structs, functions, namespaces, template function classes, concepts
9. 43:47Implicit Exports
10. 47:39include and modules including a header in the module purview is not a good idea
11. 49:05Global Module Fragment . Only preprocessor directives allowed • Declarations not used in the named module are discarded and not • Use for headers which rely preprocessor state from the includer
12. 50:21Header Units
13. 52:11Advice for Headers Your own header. Try to convert it into a module including in the global module fragment
14. 53:10Advantages encapsulation and information hiding
15. 55:24Advice Visual Studio users: Use and leam modules with small hobby side projects all others: Wait for compiler and build system support

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