0000683: return value of poll() unclear when multiple pollfds have the same fd

Austin Group Defect Tracker

Aardvark Mark IV

Viewing Issue Simple Details [ Jump to Notes ]

[ Issue History ] [ Print ]

Category

Severity

Type

Date Submitted

Last Update

0000683

[1003.1(2013)/Issue7+TC1] System Interfaces

Editorial

Clarification Requested

2013-04-24 22:16

2019-06-10 08:55

Reporter

philip-guenther

View Status

public

Assigned To

Priority

normal

Resolution

Accepted

Status

Closed

Name

Philip Guenther

Organization

OpenBSD

User Reference

Section

poll()

Page Number

1417

Line Number

46793-46795

Interp Status

---

Final Accepted Text

Summary

0000683: return value of poll() unclear when multiple pollfds have the same fd

Description

What should poll() return if multiple pollfd structures passed to it have the same 'fd' value and more than one of those has a non-zero revents on return?

First off, it should be noted that nothing in the description bans such a call, so I don't think an error return is permitted for that cause.

The RETURN VALUE section of the poll() page states:
    Upon successful completion, poll() shall return a non-negative value.
    A positive value indicates the total number of file descriptors that
    have been selected (that is, file descriptors for which the revents
    member is non-zero).

Saying that it's a count of the "file descriptors" would seem to mean that no matter how many pollfds reference the given fd, the return value must only be incremented by one. However, the systems I've tested (Solaris 10, FreeBSD 8, Linux 2.6.18, OpenBSD 5.2) all return the total number of pollfd structures that have revents non-zero.

Desired Action

Change this:
    Upon successful completion, poll() shall return a non-negative value.
    A positive value indicates the total number of file descriptors that
    have been selected (that is, file descriptors for which the revents
    member is non-zero).

to something like this:
    Upon successful completion, poll() shall return a non-negative value.
    A positive value indicates the total number of pollfd structures that
    have selected events (that is, those for which the revents member is
    non-zero).

Tags

tc2-2008

Attached Files

Relationships

There are no notes attached to this issue.

Issue History
Date Modified	Username	Field	Change
2013-04-24 22:16	philip-guenther	New Issue
2013-04-24 22:16	philip-guenther	Name	=> Philip Guenther
2013-04-24 22:16	philip-guenther	Organization	=> OpenBSD
2013-04-24 22:16	philip-guenther	Section	=> poll()
2013-04-24 22:16	philip-guenther	Page Number	=> 1417
2013-04-24 22:16	philip-guenther	Line Number	=> 46793-46795
2013-04-25 16:11	Don Cragun	Interp Status	=> ---
2013-04-25 16:11	Don Cragun	Status	New => Resolved
2013-04-25 16:11	Don Cragun	Resolution	Open => Accepted
2013-04-25 16:11	Don Cragun	Tag Attached: tc2-2008
2019-06-10 08:55	agadmin	Status	Resolved => Closed

Mantis 1.1.6[^]