True Random Numbers

[Mats]

Is this possible in C++? They really do need to be very random. It's for a test that will go through probably at least tens of millions (likely many more) of numbers, all of which need to be random.

[Cubbi]

Yes, but only if the underlying hardware provides some sort of non-deterministic entropy source, such as /dev/random on Linux. If so, you can use OS-specific API to access that device, or use the standard C++ class std::random_device.

It may be impractical (that is, very slow) to use hardware to generate tens of millions of individual values, though. I would use it as a seed to std::mt19937_64 or another PRNG with suitably large period.