You've hit on one of the improvements that Perl makes over C (and I've developed in both languages for some time).
In C, that code is meaningless, because the allocated address is on the stack, and that address disappears as soon as you return from the routine. But, as wise brother moritz has pointed out, in Perl, this allocation comes from the heap and not the stack, thus it's still available when the routine returns.
And this is a very useful feature. In C, you'd have to do something convoluted like assign some memory from the heap, pass that address into the routine, and have the routine write to the address that's been passed in, trusting that there's no buffer overrun. Ugh.
Perl just does it better! :)
Alex / talexb / Toronto
Thanks PJ. We owe you so much. Groklaw -- RIP -- 2003 to 2013.