Task Runtime

A minimal C++23 thread pool + future-based task runtime built as a learning excersize.

Features:

• Schedule independent tasks concurrently
• Runtime::submit() is thread-safe and may be called concurrently from multiple threads while the Runtime is alive
• Stores submitted callables and arguments in a type-erased task wrapper for later execution
• Performs minimal copies when storing work for later execution
  • rvalue callables and arguments are moved into task-owned storage without copies
  • copyable lvalue callables and arguments are copied once into task-owned storage
  • copy-only lvalue callables can also be submitted and run later
  • stored callables and arguments preserve value category at invocation
• Retrieves void or value results through futures
• Propagates task exceptions through futures
• Runtime destruction waits for submitted work to finish
• Dropping a Future does not cancel the task

// type-erased
auto future1 = runtime.submit(func1, arg1, arg2);
auto future2 = runtime.submit(func2, arg1);
// block thread until value is available
auto val1 = future1.await();
// progress can be made on future2 while waiting for future1
auto val2 = future2.await();

Requirements

Linux Packages

sudo apt update

sudo apt install \
    build-essential \
    gcc g++ \
    clang clangd clang-tidy \
    cmake \
    ninja-build \
    gdb \
    valgrind

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Tooling Overview

CMake

Project/build system generator.

GCC

Primary production compiler.

Clang

Recommended development compiler.

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Build Presets

This project uses CMakePresets.json for simplified builds.

Available presets:

• gcc-debug
• clang-debug
• gcc-release

The configure step also generates compile_commands.json at the repository root. VSCode and clangd use that file for accurate diagnostics and code navigation.

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Build And Test

cmake --workflow means configure the preset, build the targets, and run the tests.

Clang Debug

cmake --workflow --preset clang-debug

GCC Release

cmake --workflow --preset gcc-release

Test Only

Run all registered test cases after a build:

ctest --preset clang-debug

Run one test case:

ctest --preset clang-debug -R RuntimeTest.ThirdTaskWaitsForWorkerAvailability

Run Example

./build/clang-debug/example_basic

For manual control, use the underlying configure, build, and ctest commands with the same preset name.

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VSCode Setup

This repository is configured for clangd.

1. Install the VSCode clangd extension.
2. Configure the project with a preset, for example:

cmake --preset clang-debug

3. Open the workspace in VSCode.
4. If diagnostics do not appear immediately, run clangd: Restart language server.

The workspace settings in .vscode/settings.json are already set up to point clangd at compile_commands.json.

Include-hygiene checks are configured in .clang-tidy. Some missing direct includes may show up in clang-tidy before they appear as clangd squigglies.

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Sanitizers

Sanitizers are enabled in debug presets.

They help detect:

• memory bugs
• undefined behavior

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Recommended Development Workflow

Daily Development

• clang-debug

Final Validation

• gcc-release

Implementation

Detailed design notes live in DESIGN.md.

Language concepts:

• concurrency
• task scheduling
• move semantics
• templates

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