Date: Mon, 8 Dec 1997 08:01:15 -0500 (EST) From: "David E. Cross" <dec@phoenix.its.rpi.edu> To: Julian Elischer <julian@whistle.com> Cc: Luigi Rizzo <luigi@labinfo.iet.unipi.it>, hackers@FreeBSD.ORG Subject: Re: Why FIONREAD has no dual for write ? Message-ID: <Pine.BSF.3.96.971208075957.4595A-100000@phoenix.its.rpi.edu> In-Reply-To: <Pine.BSF.3.95.971207230045.20612F-100000@current1.whistle.com>
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On Sun, 7 Dec 1997, Julian Elischer wrote: > On Sat, 6 Dec 1997, Luigi Rizzo wrote: > > > I think I already brought this out but recent discussion on mpegtv > > suggests to bring this out again. > > > > FIONREAD tells you how many bytes you can read before blocking. > > > > There is no FIONWRITE call (how many bytes you can write before > > blocking) which would be nice to have, instead of having to resort to > > non-blocking writes. > > but it could change between the time you do that call and the time that > doo the write (you could be sharing a file descriptor, or you could be > sharing a device) so you may have to handle the blocking write anyhow. This is true even for FIONREAD, you could be sharing a file descriptor, and another process could read that data before you do. -- David Cross ACS Consultant
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