Re: method of ID'ing

$$ which i'm thinking can be reset at one point or another.

As long as you're on a system that uses incremental process ID's, you will probably be safe. Process ID's cycle when the maximum has been reached (I think it's 65535 on my system) when they're incremental, but forking that often in a single second is very unlikely.

However, Not all PIDs are simple incremental. Some are randomly chosen, and in that case, especially with short running scripts, you have a greater chance of having two identical IDs.

My concern doesn't deal with $^T

It contains the start time of the program (read: interpreter), which can cause problems if your interpreter is a long running interpreter like mod_perl or one of the many fast-perl-CGI things that avoid forking interpreters. Better is to use time, which returns the current time.

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Comment on Re: method of ID'ing

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Re: Re: method of ID'ing by Molt (Chaplain) on Apr 13, 2002 at 19:10 UTC
Good point on the $^T bit, I missed that. I'd actually think it was more of a problem with a short-lived task though such as a CGI. For example, if a CGI took a maximum of ten seconds to run then there'd only be ten possible values, increasing the possibility of a clash? On another note you may hit $$ problems if the same process wants multiple IDs, but by this point you'd be wise to look at something like class::singleton to guarantee a single-point ID manager.	[reply]

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Re: Re: method of ID'ing
by Molt (Chaplain) on Apr 13, 2002 at 19:10 UTC

Good point on the $^T bit, I missed that. I'd actually think it was more of a problem with a short-lived task though such as a CGI. For example, if a CGI took a maximum of ten seconds to run then there'd only be ten possible values, increasing the possibility of a clash?

On another note you may hit $$ problems if the same process wants multiple IDs, but by this point you'd be wise to look at something like class::singleton to guarantee a single-point ID manager.

[reply]