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According to David Cheney:
> $MSGQID = msgget(pack("L",0x0abcdef),(IPC_CREAT | 00660)) or die;
> $MSGQID = msgget("filename",(IPC_CREAT | 00660)) or die;

The first parameter to all the System V IPC "get" functions (semget,
shmget, msget) should be a numeric value -- not a packed string, and
_definitely_ not a filename.

$MSGQID = msgget(0x0abcdef, (IPC_CREAT | 00660)) or die;

--
Chip Salzenberg, aka <chs@nando.net>
"Hey, it's the Miss Alternate Universe Pageant!"
-- Crow T. Robot, MST3K: "Stranded In Space"

> The first parameter to all the System V IPC "get" functions (semget,
> shmget, msget) should be a numeric value -- not a packed string, and
> _definitely_ not a filename.
>
> $MSGQID = msgget(0x0abcdef, (IPC_CREAT | 00660)) or die;

I've been getting questions internally (to HP) about this too. Does
the IPC extension have ftok?

Jeff

I've used the following hack...

my ($junk, $INO, $junk) = stat("$BASE/bin/@_");
my ($KEY) = 0xdc000000 | $INO; # arbitrary, my initials
$MSGQID = msgget($KEY,(01000|0660)) or ... # IPC_CREAT | rw-rw----

to create the message queue using a KEY that is the inode # of the program
that will process messages on the queue. I guess its pretty close to what
ftok() does (though I haven't looked at the code) and ftok() docs say that
you can create your own KEY any way you like. I guess the only thing to
watch out for is collisions.

A nifty little kicker is a piece I wrote to replace the KEY with the program
name in ipcs(1) output, thus showing queue status for each program. First,
create a KEY to filename reverse hash:

# map program inode -> program name for later pasting into ipcs KEY field
opendir(BIN,$BIN); @PGMS = readdir(BIN);
foreach (@PGMS) {
$KEY = map_filename_to_key($_);
$PGMS{$KEY} = sprintf("%-18.18s",$_);
}

Then, get the ipcs output in a string, replace, and print:

$Q = `ipcs -qa | grep 0xdc &`;
foreach (keys(%PGMS)) { $Q =~ s|$_|$PGMS{$_}|s; } # paste pgm names
print "T ID KEY MODE OWNER GROUP CREATOR CGROUP CBYTES QNUM QBYTES LSPID LRPID STIME RTIME CTIME\n$Q\n";

Neat!

suggestions > dcheney@austin.ibm.com :)

Dave
----

Jeff Okamoto wrote:
>
> > The first parameter to all the System V IPC "get" functions (semget,
> > shmget, msget) should be a numeric value -- not a packed string, and
> > _definitely_ not a filename.
> >
> > $MSGQID = msgget(0x0abcdef, (IPC_CREAT | 00660)) or die;
>
> I've been getting questions internally (to HP) about this too. Does
> the IPC extension have ftok?
>
> Jeff
>

-----------------------------------------------------------------------------
David J. Cheney Electronic Commerce Services
(512) 838-8017 (T/L 678) IBM Networked Application Services
http://www.austin.ibm.com/~dcheney 11400 Burnet Road, Austin, TX 78758
-----------------------------------------------------------------------------

> > The first parameter to all the System V IPC "get" functions (semget,
> > shmget, msget) should be a numeric value -- not a packed string, and
> > _definitely_ not a filename.
> >
> > $MSGQID = msgget(0x0abcdef, (IPC_CREAT | 00660)) or die;
>
> I've been getting questions internally (to HP) about this too. Does
> the IPC extension have ftok?

I'll put it into the next version when I get 'A Round Tuit'.


-- Jack Shirazi, JackS@slc.com