beman.execution26: Building Block For Asynchronous Programs

beman.execution26 provides the basic vocabulary for asynchronous programming as well as important algorithms implemented in terms of this vocabulary. The key entities of the vocabulary are:

• scheduler used to control where operations are executed.
  • The key operation is schedule(scheduler) -> sender.
• sender used to represent work.
  • The key operation is connect(sender, receiver) -> operation-state.
• receiver used to receive completion notifications.
  • There are multiple operations on receivers:
    • set_value(receiver, args...) for successful completions.
    • set_error(receiver, error) to report errors.
    • set_stopped(receiver) to report cancellation.
• operation-state to represent a ready to run work graph .
  • The key operation is start(state).

Using these operations some fundamental algorithms are implemented, e.g.:

• just(args...) as the starting point of a work graph without a specified scheduler`.
• let_value(sender, fun) to produce a sender based on sender's results.
• on(scheduler, sender) to execute sender on scheduler.
• transfer(sender, scheduler) to complete with with sender's results on scheduler.
• when_all(sender ...) to complete when all senders have completed.
• bulk(...) to executed execute work, potentially concurrently.

Implements: std::execution (P2300).

Help Welcome!

There are plenty of things which need to be done. Some of these are listed in the issues section. Other contributions are, of course, also welcome. Aside from contributing code the project welcomes reports on usage experience, code reviews, defect reports, features requests, etc. There are plenty contribution opportunities.

If you want to contribute, you won't be left alone! Please e-mail Dietmar Kühl if you want help or mentoring for contributing to the library.

Build

Library	Linux	MacOS	Windows
build

The following instructions build the library and the examples:

cmake -B build
cmake --build build

The implementation compiles and passes tests using clang, gcc, and MSVC++.

Examples

• <stop_token> example: Compiler Explorer