Outdated

My original plan was it to write in this post about the next rules to error handling. But I changed my plan to write about the future: contracts in C++20.

After the last post to executors, I can finally write about the unified futures. I write in the post about the long past of the futures and end my detour from the C++ core guidelines.

A few weeks ago, one of the authors of the proposal to the futures in C++ Felix Petriconi wrote me an E-Mail. He said my article about std::future Extensions is quite dated. Honestly, he is right. The future of the futures changed mainly because of the executors.

Two weeks ago, the ISO C++ standard meeting took place in Jacksonville.  Today I want to make a short detour and write about the revolutionary decision that was made in the Jacksonville meeting. Additionally, I refer to the post C++ Will no Longer Have Pointers by Fluent C++. The standard committee decided that pointers will be deprecated in C++20 and will, with a very high probability, be removed in C++23.

The unification of templates, concepts, and placeholders goes on. This time, I will look closely at constrained (concepts) and unconstrained (auto) placeholders in the context of templates.

Task blocks use the well-known fork-join paradigm for the parallel execution of tasks.

Transactional memory is based on the idea of a transaction from the database theory. Transactional memory shall make the handling of threads a lot easier. That is for two reasons. Data races and deadlocks disappear. Transactions are composable.

Tasks in the form of promises and futures have in C++11 an ambivalent reputation. On the one hand, they are much easier to use than threads or condition variables; conversely, they have a significant deficiency. They can not be composed. C++20 will overcome this deficiency.

Forecasts about the future are difficult. In particular, when they are about C++20. Nevertheless, I will look into the crystal ball and write in the following posts about what we will get with C++17  and what we can hope for with C++20.

Monads in C++? What a strange name for a post. But it's not so strange. With std::optional, C++17 gets a monad. The ranges library from Eric Niebler and the extended futures are also monads. For both, we can hope for in C++20.