Re^3: Resource management (updated)

[roboticus]

pwagyi:

No, that's not what was meant. Normally, you don't have to worry about it, because perl uses reference counting, rather than delayed garbage collector. So once the value is no longer accessible, it's automatically cleaned up. In this respect, perl is much more like C++ with RAII where you can just let the destructor handle cleanup for you. Like this:

sub read_file {
   open my $FH, '<', 'FileName' or die $!;
   while (<$FH>) {
      ....process lines...
   }
}

If you don't store $FH in some persistent location, then once read_file returns, then 'FileName' is already closed, because $FH is no longer accessible.

You need to be careful (i.e. manual management) only when you're persisting the variable:

# Here we're at the top level of a script
open my $FH, '<', 'FileName' or die $!;
while (<$FH>) {
   ... process lines ...
}

# Now we're sleeping for 5000 seconds, and FileName is still open, bec
+ause the program still
# has $FH accessible.
sleep 5000

So don't put resources in global variables, and only use resources for the duration of a subroutine, and you'll rarely need to worry about it.

For your XS stuff, you'll either have to manually manage the resource if it's coming from C, or you can make your code object oriented and let DESTROY handle it. If you present a bit more detail of your use case, you can get more specific advice.

...roboticus

When your only tool is a hammer, all problems look like your thumb.