Pet Bugs?

benreece asks: "During my few years as a programmer/developer I've come across some strange bugs. Recently I found that Microsoft's VB/VBScript(ASP) round function has problems (for example, 'round(82.845)' returns '82.84' instead of '82.85'). It took me an annoyingly long time to realize the problem wasn't mine. I'm wondering what other obscure, weird, and especially annoying bugs in languages/compilers/etc have frustrated other developers." Memorable bugs. Every developer has one. What were yours?

Comments

In all seriousness, random libs *suck*

[edremy]

random() only returns 666 if you use a demon seed!

My favorite "bugs" are the truly horrible random number functions in almost every single language library on earth. They're usually linear congruential generators: fast, but utterly useless for any work that requires serious "randomness" such as Monte Carlo simulations. They have very short recurrence times, strong sequential correlation, etc.

Back in grad school, I had to substitute the Knuth ran3 routine for the supplied C library functions in both gcc and xlc since they were just awful.

Fast forward 8 years. I made the stupid assumption that since Java was a new language and that horrible problems with random number generators were well known that Sun would actually provide a decent RNG. Nope: just as badly flawed as the C one.

I suspect this is simply something to give up tilting at windmills about: random() is good enough for simple games and anyone doing real work knows to stay the hell away.