Re: Re: "unique" filename?

Actually, that wouldn't prevent duplicate filenames at all, depending on how fast you're generating filenames. For example, look what the following does:

while (1) {
    print $$.time."\n";
}
[download]

Also, on Win32, there's a non-zero chance of a PID being reused.

Comment on Re: Re: "unique" filename? Download Code

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Re: Re: Re: "unique" filename? by 2501 (Pilgrim) on Dec 04, 2000 at 03:33 UTC
When you log into a site, you have two options. You can start running a script from a new connection or you can use an existing connection. Since only one person can be using a PID at a time, the combination of time and PID is fine.	[reply]
Re: Re: Re: Re: "unique" filename? by quidity (Pilgrim) on Dec 04, 2000 at 05:12 UTC
That might be so, but if you need the file to remain on the server for a while (as part of session management perhaps), then your method breaks. With some operating systems, for instance OpenBSD, there is a chance that the same PID will occur twice within one second, especially on a heavily loaded site. You are also at risk of exposing your machines current position in the PID list, which could be of use to someone hoping to exploit the way someone has used the PID and time to seed a random number generator. Use the modules, and you insulate yourself from these problems. CPAN is your friend.	[reply]
Re: Re: Re: Re: Re: "unique" filename? by repson (Chaplain) on Dec 04, 2000 at 07:02 UTC
If you used Time::Hires then it is far less likely you would get the same value from time(). But then since you are already using a modules from CPAN it would be better to use one meant for what you are doing.	[reply]
Re: Re: Re: Re: Re: "unique" filename? by merlyn (Sage) on Dec 04, 2000 at 05:14 UTC
An openBSD system can fork 30,000 processes in one second? Are you kidding? -- Randal L. Schwartz, Perl hacker	[reply]


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