cpp-shared-ref

A cross-platform, C++17 compatible, non-atomic reference-counting smart pointer, made for myself as a replacement for the atomic std::shared_ptr.

shared_ref emulates most of std::shared_ptr's API and functionality, with the most important difference being that the reference increments and decrements are not atomic. The premise is that a reference-counting smart pointer can be very useful in contexts outside of multithreading, in which atomicity is not needed, being just useless overhead. This is why I tried making my own version of std::shared_ptr.

Right now, shared_ref doesn't fully conform to the std::shared_ptr specification of C++17. This is a list of missing features from my version:

• Not allocator-aware
• No support for arrays
• No support for -fno-exceptions
• Deprecated features as of C++17 are missing (for good)

The code is unit-tested. Almost all public functionality is tested. Also Valgrind is regularly used in development to check for memory bugs. Tested compilation on GCC 13.2 and MSVC 19.39.

If you need a specific missing feature, or need this library to work on lower versions of C++, feel free to open up an issue.

Usage

With CMake, you can use this library as a submodule:

git submodule add -b stable -- https://github.com/SimonMaracine/cpp-shared-ref <path/to/submodule>

add_subdirectory(<path/to/submodule>)
target_link_libraries(<target> PRIVATE cpp_shared_ref)

To build with tests:

set(CPP_SHARED_REF_BUILD_TESTS ON)

Development takes place on the main branch. The stable branch is meant to be used.

Example

#include <iostream>
#include <cpp_shared_ref/memory.hpp>

int main() {
    sm::weak_ref<int> foo;

    {
        sm::shared_ref<int> bar {sm::make_shared<int>(5)};
        std::cout << *bar << '\n';

        foo = bar;
    }

    auto baz {foo.lock()};

    if (baz) {
        std::cout << "This never gets printed\n";
    }
}