You're right: I didn't do any error checking on the flock() calls. I should have. But (based on the assumptions I made in my code snippets: files exist, no interrupts, etc) it should never return until it gets a lock unless you're using LOCK_NB anyway, since it's a blocking call.

But that's not really the primary point of my post. I was wondering if anyone knew of any problems with opening the_file multiple times, once for locking and once for reading/writing/etc. Update: No one seems to have found anything wrong with it, so for now I'm assuming it's a valid technique (even if my sample code doesn't implement it completely correctly :) Please tell me if you can see anything wrong with the basic technique I presented in my original node, independant of the actual code used to implement it.

Thanks,

Alan

Update, re AN's comments: It's sample code. It was meant to demonstrate a point, not to be complete, or even to work (since I didn't know if it did). I think my point and question were demonstrated more clearly and concisely by making these assumptions instead of by increasing the sample code beyond the size of easy readability.

Thank you for your clarifications and comments on my methods. Clearly, knowing the environment you're working in plays an important part in determining what assumptions are safe to make and which aren't, in your specific case. But without some assumptions, you can't even count on things as basic as the behavior of the particular OS you assume you're running under.

In reply to Re: A flock()alypse now by ferrency
in thread A flock()alypse now by ferrency

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