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Copper is a C++ library of a powerful queue object for communication between threads. It is based on Go's channels and follows the quote:

Don't communicate by sharing memory; share memory by communicating.

See docs/motivation.adoc for a high-level description of what Copper is capable of and how it stands out from previous C / C++ implementations of queues and Go-like channels.

Copper has...

• only a single header to include.
• no deadlocks; no race conditions; no undefined behavior; no polling.
• support for multiple producers and multiple consumers.
• an API based on that of std to avoid style clashes.

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Quick Example

#include <future>
#include <iostream>
#include "copper.h"

copper::buffered_channel<int> channel_1;
copper::buffered_channel<int> channel_2;

void producer_1() {
    // Push the numbers 0 to 9 into channel_1.
    for (auto i = 0; i < 10; ++i) {
        (void) channel_1.push(i);
    }
    channel_1.close();
}

void producer_2() {
    // Push the numbers 0 to 9 into channel_2.
    for (auto i = 0; i < 10; ++i) {
        (void) channel_2.push(i);
    }
    channel_2.close();
}

void consumer() {
    // Until both channel_1 and channel_2 are closed, get the next message from either and print it.
    while (copper::select(
        channel_1 >> [](int x) { std::cout << "Message from producer 1: " << x << std::endl; },
        channel_2 >> [](int x) { std::cout << "Message from producer 2: " << x << std::endl; }
    ) == copper::channel_op_status::success);
}

int main() {
    const auto p1 = std::async(producer_1);
    const auto p2 = std::async(producer_2);
    const auto c = std::async(consumer);
    return 0;
}

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More Information

API Reference

See docs/reference.adoc for a detailed reference of the public code interface.

Efficiency & Benchmarks

See docs/techdetails.adoc for technical information about efficiency and some benchmarks.

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Dependency managers

FetchContent

include(FetchContent)
FetchContent_Declare(
  copper
  GIT_REPOSITORY https://github.com/atollk/copper
  GIT_TAG        v1.1
)
FetchContent_MakeAvailable(copper)
target_link_libraries(MyProject Threads::Threads copper)

CPM

CPMAddPackage(
  GITHUB_REPOSITORY atollk/copper
  VERSION 1.1
)
target_link_libraries(MyProject Threads::Threads copper)