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[Patch] Improve IO::Socket::connected() documentation #14199
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From [email protected]Created by [email protected]Attached doc patch for IO::Socket::connected() is the eventual disposition of http://www.nntp.perl.org/group/perl.perl5.porters/2014/08/msg218522.html It is essentially identical to the suggested wording posted here: http://www.nntp.perl.org/group/perl.perl5.porters/2014/10/msg221699.html the only differences being some minor wordsmithing. Perl Info |
From [email protected]0001-Improve-connected-doc.patchFrom 1b346f7bfbfcf3107b3b89c8208bf0bf00ac0840 Mon Sep 17 00:00:00 2001
From: "Glenn D. Golden" <[email protected]>
Date: Tue, 28 Oct 2014 04:24:04 -0600
Subject: [PATCH] Improve connected() doc
---
dist/IO/lib/IO/Socket.pm | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/dist/IO/lib/IO/Socket.pm b/dist/IO/lib/IO/Socket.pm
index 625c71a..c98ea0b 100644
--- a/dist/IO/lib/IO/Socket.pm
+++ b/dist/IO/lib/IO/Socket.pm
@@ -499,8 +499,23 @@ C<use> declaration will fail at compile time.
=item connected
-If the socket is in a connected state the peer address is returned.
-If the socket is not in a connected state then undef will be returned.
+If the socket is in a connected state, the peer address is returned. If the
+socket is not in a connected state, undef is returned.
+
+Note that connected() considers a half-open TCP socket to be "in a connected
+state". Specifically, connected() does not distinguish between the
+B<ESTABLISHED> and B<CLOSE-WAIT> TCP states; it returns the peer address,
+rather than undef, in either case. Thus, in general, connected() cannot
+be used to reliably learn whether the peer has initiated a graceful shutdown
+because in most cases (see below) the local TCP state machine remains in
+B<CLOSE-WAIT> until the local application calls shutdown() or close();
+only at that point does connected() return undef.
+
+The "in most cases" hedge is because local TCP state machine behavior may
+depend on the peer's socket options. In particular, if the peer socket has
+SO_LINGER enabled with a zero timeout, then the peer's close() will generate
+a RST segment, upon receipt of which the local TCP transitions immediately to
+B<CLOSED>, and in that state, connected() I<will> return undef.
=item protocol
--
2.1.3
|
From @tonycozOn Sat Nov 01 10:20:26 2014, gdg@zplane.com wrote:
Thanks, applied as 7eb3f2c. Tony |
|
The RT System itself - Status changed from 'new' to 'open' |
|
@tonycoz - Status changed from 'open' to 'resolved' |
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Migrated from rt.perl.org#123096 (status was 'resolved')
Searchable as RT123096$
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