Re: [boost] boost::random, header-only, boost::uuids::detail::seed_rng, and UWP development

Andrey Semashev wrote:

On Tue, Sep 12, 2017 at 4:27 PM, degski via Boost wrote:

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On 12 September 2017 at 15:40, James E. King, III via Boost < boost@lists.boost.org> wrote:

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The older WinCrypt calls are not available in some Windows platforms going forward, so this is going to become a problem pretty quickly for the community.

You worry too much, just call rand_s https://msdn.microsoft.com/en-us/library/sxtz2fa8.aspx (the same thing under the hood, but taking care of any WinCrypt BCrypt, whatever issues).

I assume, this is MSVC-specific, i.e. doesn't work with MinGW?

In addition, "The rand_s function requires that constant _CRT_RAND_S be defined prior to the inclusion statement for the function to be declared, as in the following example: #define _CRT_RAND_S #include " which probably means that if is included prior to the header that wants to use rand_s, it will be unavailable. We could use RtlGenRandom instead, which is what rand_s calls. Not sure if that works under UWP. To answer the question in the original post, yes, making random_device header-only would indeed be useful, as long as we don't include . There's no need to include the implementation from seed_rng in its entirety though, it's more complicated than need be because it tries to support the case in which a device isn't available. Since the construction of random_device can fail, it can be a lightweight wrapper over /dev/urandom / CryptGenRandom, without all the SHA business.