On Jul 26 12:17, Corinna Vinschen wrote: > On Jul 26 01:51, Mark Geisert wrote: > > Hi Corinna, > > > > On Thu, 26 Jul 2018, Corinna Vinschen wrote: > > > On Jul 25 15:06, Yaakov Selkowitz wrote: > > > > > From discussion on IRC: > > > > > > > > <yselkowitz> corinna, just sent a patch for _POSIX_ASYNCHRONOUS_IO as a > > > > follow-up to the AIO feature, but am still wondering about > > > > _[POSIX|PC]_ASYNC_IO > > > > [snip] > > > > <corinna> in terms of _PC_ASYNC_IO, the test might be a bit tricky > > > > <corinna> let me check > > > > <corinna> actually, no > > > > <corinna> it's easy > > > > <corinna> Mark implemented the stuff with pread/pwrite only on disk > > > > files > > > > <corinna> but otherwise it's device independent in that he implemented a > > > > workaround for pipes and stuff > > > > <corinna> so, in theory we can just return 1 > > > > > > > > I'm not sure how to test this atm, but based on the above I have made > > > > the following patch so this doesn't get lost. > > > > > > > > Yaakov Selkowitz (1): > > > > Cygwin: fpathconf: update _PC_ASYNC_IO return value > > > > > > > > winsup/cygwin/fhandler.cc | 1 + > > > > 1 file changed, 1 insertion(+) > > > > > > > > -- > > > > 2.17.1 > > > > > > Mark? Any comment you want to make? > > > > Thanks for asking. Your characterization of my implementation is correct. > > The intent is for aio_* async I/O to be supported on all descriptors. On > > the most useful case of binary local disk files, inline pread|pwrite is > > used. But I wanted to make sure the AIO interface would do the right thing > > on other kinds of descriptors without bothering the user about it. > > > > So if the intent of the _PC_ASYNC_IO flag is to say that async I/O is > > supported generally, I do think setting it to 1 is appropriate. That is, > > if it's talking about the aio_* interfaces. If there's an O_ASYNC defined > > for app coders, my recent contribution doesn't address that at all. > > Good question. O_ASYNC is a BSD invention, and it's not defined in > POSIX at all. Since we're in POSIX territory, _PC_ASYNC_IO and > _POSIX_ASYNC_IO can only refer to async io as implemented by your new > aio code: > > - _POSIX_ASYNCHRONOUS_IO defines if the implementation supports async io > at all. > - _POSIX_ASYNC_IO defines if the file in question supports async io.
Offline all day due to a major hardware breakdown. The heat or something. My server died the mainboard death. I'm running a replacement system right now with *much* less power. Will take a week or more to get an adequate replacement so I'm on half power for a while. Oh well, enough lamenting. Yaakov, please push your patch. Thanks, Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat
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