[cfe-dev] [libcxx] random_device for Windows needs more storage

[Aaron Ballman]

rand_s() is a much better solution.  :-)

~Aaron

On Mon, Oct 7, 2013 at 5:53 PM, Yaron Keren <yaron.keren at gmail.com> wrote:
> Hi,
>
> Just found out both Visual C++ and MingW supply the rand_s() function
> (implemented in MSVCRT), which wraps one of the above functions in a very
> easy to use and version:
>
> http://msdn.microsoft.com/en-us/library/sxtz2fa8.aspx
>
> Microsoft own random_device uses it,
>
> Yaron
>
>
>
> 2013/10/8 Aaron Ballman <aaron at aaronballman.com>
>>
>> On Mon, Oct 7, 2013 at 5:31 PM, Yaron Keren <yaron.keren at gmail.com> wrote:
>> > Nick, I have seen RtlGenRandom, but I didn't initally use it since
>> > Microsoft
>> > is recommending to use CryptGenRandom instead:
>> >
>> >
>> > http://msdn.microsoft.com/en-us/library/windows/desktop/aa387694(v=vs.85).aspx
>> >
>> > [The RtlGenRandom function is available for use in the operating systems
>> > specified in the Requirements section. It may be altered or unavailable
>> > in
>> > subsequent versions. Instead, use the CryptGenRandom function.]
>> >
>> > Due to backward compatibility it's very low chance RtlGenRandom will
>> > actually go away, I'll use it.
>>
>> I don't believe we should be using this function.  Technically, the
>> documentation states this is available for use with the operating
>> systems listed in the Requirements section, which only lists XP and
>> Server 2003.  Relying on this outside of those platforms is not only
>> bad form, but to boot, in order to use them, you need to dynamically
>> load SystemFunction036 from AdvApi32.dll.
>>
>> ~Aaron
>
>