Which I believe is what you’re looking for.

I don't think so. Suppose he'd captured the seed, then what? This is certainly not what he want:

sub func() {
    srand $CONSTANT;
    ... do stuff using a known sequence ...
}
my $seed = srand;
my $random1 = rand;
func();
srand $seed;  # Get back to "random" sequence again?
my $random2 = rand;
[download]

Now $random1 and $random2 are the same.

You'd have to keep track of how many random numbers one has generated, and each time you'd call srand with the original seed again, you'd have to call rand that times, discarding the result before continuing.