Does stdlib's rand() always give the same sequence?

Question

I quite like being able to generate the same set of pseudo-random data repeatedly, especially with tweaking experimental code. Through observation I would say that ran

Answer 1

No.

The C standard says:

If srand is then called with the same seed value, the sequence of pseudo-random numbers shall be repeated.

But nowhere does it say what the sequence of pseudo-random numbers actually is - so it differs across implementations.

The only guarantee made is that rand() will give the same sequence of numbers for a given seed for a given implementation. There's no guarantee that the sequence will be the same across different machines or different architectures - and it almost certainly won't be.