rand() on Win vs. BSDI?

[sholmlund]

Apologies if this has been covered already. I couldn't find the answer and I'm a newbie.

Rand()appears to work WITHOUT using srand() on my local Win2K/IIS/PHP4 combination but fails on my Web host's BSDI/Apache/PHP4 setup. (Fails meaning $Number always equals 1.)

This was easy to solve once I located the problem but the fact that it worked in one place had me scratching my head for a while.

If I'm accurate about this behavior, how many other scenarios are there like this?

[[deleted]]

According to the manual you are required to srand() before you rand(), so the fact that it worked on win is nice, but you should not really have used it that way in the first place. :-)

[sholmlund]

Thanks for the reply. I'll be sure to check the manual first from now on.

It actually would have been nicer if it had failed the same on Windows as on BSDI (assuming nothing else is causing the observed behavior).

But lesson learned.

[kparker]

so the fact that it worked on win is nice,

No, it's not at all nice--rand() is supposed to give the same sequence if you don't call srand() first, by very deliberate design. (For one thing, how else are you supposed to test a RNG or a program using one, unless you can set it to some known starting point?) It's been this way, as far as I can tell, from Day 1 of the C library, and has been mandated by the C standard from the moment it was proposed. So if it doesn't work right on Win, what else is wrong there?

[[deleted]]

Still, from a "normal" user's point of view it's nice not to have to seed before rand().

Just like PHP does not require you to declare vars (also mandatory in C)

:-)