#42 udpInput() signals false EOF

[Don Porter]

When a Tcl_DriverInputProc() returns the value 0,
the core I/O parts of Tcl take that to mean a signal
of EOF on the channel. udpInput() is returning 0
in several places when it does not intend that meaning.

See http://core.tcl.tk/tcl/tktview/1ff0660e6e
for a rundown of the corrections that are needed.

The Tcl 8.5.16 release candidate contains revisions
where the Tcl I/O core has started believing the
claims sent back from channel drivers. If a driver
says it's reached EOF, the I/O core won't call its
input proc anymore. As things currently stand, these
bugs will have to be fixed for tcludp to work with
Tcl 8.5.16.

For the sake of the existing deployed extensions,
I'll be looking into what accommodations might be
offered before 8.5.16 release, but the sooner the
bugs in extensions are fixed, the better.

[Don Porter]

I had to do some guess work on this.
May need review and revision.

But on the demo script I have, this patch
solves the problem with Tcl 8.5.16 and Tcl 8.6.2.

[Huub Eikens]

Don,

I'm abroad for the last three weeks (and 1 week to come) with limited email access hence my late response. Since I don't have my tclupd development environment with me, I cannot properly test your patch. I can commit the change though if you (or someone else) can confirm that this patch is correct.

Regards,

Huub

[Don Porter]

I'd greatly prefer review by an independent set
of eyes -- ideally those of someone invested in
the success of tcludp.

As things stand, the Tcl 8.5.16 release will
accommodate existing tcludp releases. Tcl 8.6.2
will not, and I expect tcludp packages to fail with
it unless this patch, or some revision of it, is
accepted and a corrected tcludp release restores
things.

[Huub Eikens]

I'll take a look at it when I'm back.

[Huub Eikens]

I am unable to reproduce the problem. What I've done so far is:
1. Downloaded and build the tcl 8.5.15 version using the link http://prdownloads.sourceforge.net/tcl/tcl861-src.zip
2. Build the tcludp package (without your patch) against it.
3. Run the following script as described in the ticket (https://groups.google.com/forum/#!topic/comp.lang.tcl/sRr678PXFfM) :

package require udp 
set host localhost; set port 53530

## udp sender 
proc udp_puts {host port} { 
    set s [udp_open] 
    fconfigure $s -remote [list $host $port] -buffering none -translation binary 
    puts $s "Hello, World" 
    close $s 
}

# A simple UDP server 
proc udpEventHandler {sock} { 
    set pkt [read $sock] 
    set peer [fconfigure $sock -peer] 
    puts "$peer: [string length $pkt] {$pkt}" 
    return 
} 
proc udp_listen {port} { 
    set srv [udp_open $port] 
    fconfigure $srv -buffering none -translation binary 
    fileevent $srv readable [list ::udpEventHandler $srv] 
    puts "Listening on udp port: [fconfigure $srv -myport]" 
    return $srv 
} 
set sock [udp_listen $port]

proc sendMessages {} {
    global host
    global port
    udp_puts $host $port
    after 1000 sendMessages
}
sendMessages
vwait forever

---

The output I get is:
127.0.0.1 58965: 12 {Hello, World}
127.0.0.1 58965: 1 {
}
127.0.0.1 39474: 12 {Hello, World}
127.0.0.1 39474: 1 {
}
127.0.0.1 49044: 12 {Hello, World}
127.0.0.1 49044: 1 {
}
...
which indicates to me that tcludp is working fine.

All above was done on a Fedora 17 virtual machine using Virtual Box.

[Don Porter]

Please demonstrate the problem with
the release candidate of Tcl 8.6.2:

ftp://ftp.tcl.tk/pub/tcl/tcl8_6/tcl862rc1-src.zip

[Huub Eikens]

Solved in version 1.0.11