Bug 7609

Summary:	poll(2) semantics on read-EOF differ from Solaris 10 semantics
Product:	File System	Reporter:	Matti Aarnio (mea)
Component:	Other	Assignee:	fs_other
Status:	REJECTED WILL_NOT_FIX
Severity:	normal	CC:	protasnb
Priority:	P2
Hardware:	i386
OS:	Linux
Kernel Version:	2.6.9, 2.6.15	Subsystem:
Regression:	---	Bisected commit-id:

Description Matti Aarnio 2006-12-01 03:25:43 UTC

While converting old code using select(2) to use poll(2), its deployment
on Solaris 10 SPARC machine did show that Solaris does return (in revents)
POLLEOF without POLLIN if the file (socket) is in read-EOF condition.

Linux 2.6.15 does return POLLIN even for EOF cases.
Does it return it WITH the POLLEOF flag ?  That was not looked for.

I can't entirely blame Linux for returning this result -- it is very convenient
for conversion from select() to poll(), after all, but being a mismatch against
Solaris, code portability issues raised their ugly head..
Nor can I say what happens at latter kernel versions.

Comment 1 Michael Tokarev 2007-03-29 06:55:52 UTC

There's NO POLLEOF flag on Linux.  It's Solaris-specific it seems.

Comment 2 Natalie Protasevich 2008-04-06 12:11:50 UTC

Matti, if you are still interested in such semantics, maybe you can elaborate what the flag is for in read-EOF condition. Maybe it will be possible to map this case to Linux functionality and explain the difference.