Re: [PATCHv3 02/11] run-command: report failure for degraded output just once
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Nov 5, 2015, 07:32 UTC
- Message-ID
- <xmqq4mh09a0q.fsf@gitster.mtv.corp.google.com>
- In-Reply-To
- <20151105065111.GA4725@sigill.intra.peff.net>
Jeff King <peff@peff.net> writes:
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> POSIX implies it is the case in the definition of read[2] in two ways: > > 1. The O_NONBLOCK behavior for pipes is mentioned only when dealing > with empty pipes. > > 2. Later, it says: > > The value returned may be less than nbyte if the number of bytes > left in the file is less than nbyte, if the read() request was > interrupted by a signal, or if the file is a pipe or FIFO or > special file and has fewer than nbyte bytes immediately available > for reading. > > That is not explicit, but the "immediately" there seems to imply > it.
We were reading the same book, but I was more worried about that "may" there; it merely tells the caller of read(2) not to be alarmed when the call returned without filling the entire buffer, without mandating the implementation of read(2) never to block.
Having said that,...
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>> So perhaps the original reasoning of doing nonblock was faulty, you >> are saying? > > Exactly. And therefore a convenient way to deal with the portability > issue is to get rid of it. :)
... I do like the simplification you alluded to in the other message. Not having to worry about the nonblock (at least until it is found problematic in the real world) is a very good first step, especially because the approach allows us to collectively make progress by letting all of us in various platforms build and experiment with "something that works".