Re^4: Help with references

Point taken (I think). My initial concern was that since @a1 and @a2 were "my"-ed within the function, that returning references to them might be dangerous since they go out of scope once the function returns and aren't guaranteed to stick around afterward. But perhaps this is thinking too much like C. Can you clarify these scoping issues for me?

In any case, the main point was that the function should return references to two arrays and not the contents of the two arrays (which get lumped together) leaving the second return slot empty.

Comment on Re^4: Help with references

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Re^5: Help with references by thor (Priest) on Jul 01, 2004 at 20:44 UTC
Garbage collection in perl is done by reference counting. By returning \@array, you are keeping a reference to @array, and thus it will not be garbage collected. You also have the advantage in that in perl, you are not dealing (directly) with memory addresses, so it's less likely that you'll shoot yourself in the foot. thor	[reply]
Re^5: Help with references by sgifford (Prior) on Jul 02, 2004 at 15:25 UTC
In addition to what thor says, it's important to remember that each time your code enters a block that has a `my` variable in it, like this `sub`, it creates a completely new variable (at least conceptually). So when two calls to the sub both return `\@a1`, they're returning completely different and unrelated variables. This is different than if `\@a1` were a global variable, in which case both would return the exact same reference (and so changes to one would affect the other). This is one of the really nice things about Perl over languages like C, where returning a local variable from a sub is a really bad idea.	[reply] [d/l] [select]