OpenBSD routes around POSIX

OpenBSD routes around POSIX

I actually use a deterministic random number generator in many of my programs, exactly for the purpose of reproducibility. But, I'm writing programs such as "random test generators" where a given input plus a given seed should produce the same test every time.

I also therefore use a dedicated random number class. (C++11 makes this very easy and very nice.) In fact, I use what I call "forked" random number generators, where a master generator (seeded by the test case seed) seeds child generators that I then hand to various subsystems. (Those children can be forked further for sub-subsystems, etc.)

The behavior of the whole tree depends on the original seed, but a tweak in behavior in one subsystem doesn't disturb the stream of pseudo-random numbers in another subsystem. This makes debugging and testing go much more smoothly.

All this to say: If you're writing simulation software that relies on the quality of the random numbers, reproducibility, and portability across multiple platforms, you likely abandoned the standard library rand()/random()/xrand48() a long time ago. You probably grabbed a copy of Mersenne Twister or any number of other, better generators and wrote your own wrappers around these things. I know I did eons ago. (And now with C++11's excellent random number library, I'm doing it with much less pain.)

I guess a part of me is a little surprised that 8800 packages showed up using rand() and friends. Then again, how many of them are actually negatively affected by bad random numbers?