CppCon 2015

Generic programming is a programming paradigm which makes it possible to build highly extensible and efficient libraries. In C++ it can be implemented using templates, therefore developers and users of generic libraries need to understand how the compiler works with templates. The details are important when the code using a library instantiates different templates (or specialisations), or the same templates but with different arguments as expected. Fixing such bugs can lead to difficult debugging sessions. These are not bugs in the program's runtime behaviour. These are bugs in the program's compile-time behaviour and therefore different tools are needed to find them. Tools providing insight into what happens during the compilation process are needed.

Template metaprogrammers have been pushing the limits of what is possible using templates. The way they use templates is usually more complex than what generic libraries need. Recently a number of advanced tools supporting template metaprogrammers have been built. REPL shells, debuggers, profilers are available to make it possible to see what happens during compilation.

This talk presents how these tools can be used and be useful for the developers and users of generic libraries. Insight into what happens inside the compiler can be extremely useful to understand why the code compiles slowly, behaves the way it does or to debug errors in code using generic libraries.