beman.execution: Building Block For Asynchronous Programs

beman.execution provides the basic vocabulary for asynchronous programming as well as important algorithms implemented in terms of this vocabulary.

Implements: std::execution (P2300R10).

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.

Status: Under development and not yet ready for production use.

Help Welcome!

There are plenty of things which need to be done. See the contributions page for some ideas how to contribute. The resources page contains some links for general information about the sender/receivers and std::execution.

Dependencies

Build Environment

This project requires at least the following to build:

• A C++ compiler that conforms to the C++23 standard or greater
• CMake 3.30 or later
• (Test Only) GoogleTest

You can disable building tests by setting CMake option BEMAN_EXECUTION_BUILD_TESTS to OFF when configuring the project.

You can disable building examples by setting CMake option BEMAN_EXECUTION_BUILD_EXAMPLES to OFF when configuring the project.

Library	Linux	MacOS	Windows
build

The following instructions build the library and the examples:

ln -s cmake/CMakeUserPresets.json .
cmake --workflow --list-presets
Available workflow presets:

  "debug"
  "release"
  "gcc-debug"
  "gcc-release"
  "llvm-debug"
  "llvm-release"
  "msvc-debug"
  "msvc-release"


CXX=g++-15 cmake --workflow --preset release

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

Supported Platforms

Compiler	Version	C++ Standards	Standard Library
GCC	15-14	C++26, C++23	libstdc++
Clang	22-19	C++26, C++23	libc++
MSVC	latest	C++23	MSVC STL

License

beman.execution is licensed under the Apache License v2.0 with LLVM Exceptions.

Examples

• <stop_token> example: Compiler Explorer