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I am really surprised to see everyone agreeing that a header-only implementation is preferable.

I completely agree with that sentiment.

I also agree. Header only libraries are convenient, but they don't scale well for the reasons that have already been brought up. Compile time is one issue. Also, as the library gets bigger, more and more code will be compiled into each binary that could have rather been precompiled and shared from a shared library. Most people will probably be linking against at least libstdc++ anyway, so it's no big deal to link against another library (although I only have experience with the GNU tools --- maybe the Microsoft tools are a different story). Good to see development on the threads library. In particular, the timed mutexes now seem to be passing some tests I have been doing. Cheers, Russell