Don't know why everyone is so biased aganst posters that ask for a speed tip -- not everyone sits here and trys to pre-optimize every line of code -- as for the posters post how do you know that he does not have a finnished app in which he seems the tight inner loop running too slow for his needs?

Anyways, if the unix host has a shadowed passeord file most of the time normal users are allowed to read the /etc/passwd file as it has no password entries in it. you can slurp that file before you tight loop and make a hash of usernames then just check if they are defined. This will save you (on most systems getpwnam is not cached ...) the load /etc/passwd, search /etc/passwd steps per user lookup. I had this same problem at a site that had a very large password file where getpwnam was taking 10 seconds to run per call -- it speeded up my tight loop by 20 minutes.

-Waswas

Edited: one note with this method, there is a chance for a race condition if the password file is not sorda static -- if a user is added after you make the hash and before your tight loop is done the check with give you a false negitive match or if the user is deleted before the tight loop finishes a false positive.

In reply to Re: Quick User Existance Check? by waswas-fng
in thread Quick User Existance Check? by Anonymous Monk

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