I would recommend that you look at Data::UUID

I'd second that. Works very well in my experience. Use the creation date of the files to order them.

(I'm assuming that your comments about multiple processes mean that the exact order isn't important.)

Use the creation date of the files to order them.

Since he can create several files in a short interval, so that even Time::HiRes isn't updated quickly enough (update interval is 18 times a second, on Windows), and the resolution of creation date is in general only 1 or 2 seconds, I am certain you haven't solved the OP's problem.

Since he can create several files in a short interval, so that even Time::HiRes isn't updated quickly enough (update interval is 18 times a second, on Windows), and the resolution of creation date is in general only 1 or 2 seconds, I am certain you haven't solved the OP's problem

I am less certain of your certainty ;-)

The OP apparently has multiple processes running that are dumping these files (my emphasis):

command line interface gets called extremely often and often several for these processes run at the same time

Which was why I said:

(I'm assuming that your comments about multiple processes mean that the exact order isn't important.)

The exact running order is going to be dependent on a lot of factors outside the OPs control. Depending on the exact requirements having unique filenames and a rough order may well be enough.

I will create files that look like XXX~gettimeofday()~PID.xml and sort on the time of day. If there are two files with the same time of day I will have to build in some kind of exception handeling for the sequence thing.

Thank you!

Cycling through all the PIDs within a second (or whatever is the smallest increment of time you can get) is not the problem. Hitting that cycle in one of those itervals is. And it will happen.

So what you need to do for your exception handling is to first determine how high the process counter on your machine can count (this may possibly change with OS updates, so I'd try to get that information dynamically from the OS). Then decide that if there is a difference of for examle at least half that maximum count between PIDs in your filenames, the lower block of them came after the higher block. Process them accordingly

That should do ya.

Update: grinder has /msged me that this will not work on BSD type boxes where random PID allocation (a security feature) has been configured. He's probably right, so you better talk to your admin before relying on consecutive PID allocation for the next couple of years. :-)