When to use read() or sysread()

Asked Mar 30 '16 at 16:59

Active Mar 30 '16 at 17:00

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When is sysread better than read for fetching data in perl? The perlfunc sections on sysread and read give advice that is not entirely clear on when to choose which.

In a response to another question I used Stream::Reader. As an experiment I replaced read with sysread in Reader.pm and gained 9-10% throughput. This seems too simple and - other than what I can glean from perlfunc - I am not clear on what the trade offs might be.

edited May 23 '17 at 11:59

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asked Mar 30 '16 at 16:59

G. Cito

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[ikegami beat you to it.](http://stackoverflow.com/q/36315124/176646) – ThisSuitIsBlackNot Mar 30 '16 at 17:00
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Once I get a good answer from him I'll post a response here :-D – G. Cito Mar 30 '16 at 17:03
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You should post your answer on his question and delete this one since these are duplicate questions. – ThisSuitIsBlackNot Mar 30 '16 at 17:05
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I was just about to post: *It appears to me that Stream::Reader supports streams with `:encoding` layers. As such, it can't use `sysread`.* – ikegami Mar 30 '16 at 17:14
OK so maybe the reason it returned the same results was because the data in that case was somewhat unusually boring or because I was using `Mode => "UB" ` in the constructor ... – G. Cito Mar 30 '16 at 17:21

When to use read() or sysread()

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