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<p><span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: small;">Hi Marshall, Eric,</span></p>
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Currently the libcxx configuration option LIBCXX_ENABLE_THREADS serves two purposes:</div>
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1. Enabling C++11 threading constructs like std::thread and std::mutex in the library.</div>
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2. Ensuring certain constructs are safe to be used in multi-threaded environments. This is about ensuring that any storage allocated by the library itself is properly protected using mutexes and/or atomic operations. A good example for this is the ref counting
mechanism of shared_prt<T>.</div>
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(2) is a pre-requisite for (1). But I think (2) should be able to stand on its own even without (1) - which is currently not possible.</div>
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The use case for us is that there are users who want to use shared_prt<T> (and others) in multi-threaded environments without having to enable high-level threading constructs like std::thread and std::mutex. I would also put std::atomic into the same category;
these should be available even if std::mutex and std::thread are explicitly disabled in the library.</div>
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Do you think this would be useful to the general audience of libc++? I can spin some patches if so.</div>
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Thanks.</div>
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/ Asiri</div>
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