Andrey Semashev wrote:
On Tue, Sep 12, 2017 at 4:27 PM, degski via Boost <boost@lists.boost.org> wrote:
On 12 September 2017 at 15:40, James E. King, III via Boost < boost@lists.boost.org> wrote:
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 <stdlib.h> " which probably means that if <stdlib.h> 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 <windows.h>. 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.