1. Perl version (all 3 digits)
2. O/S and platform information

Also, have you tested that everything works when you *don't* use threads, i.e., the first host gets dumped out, then the 2nd ?

Perl version is 5.8.5 Platform: Gentoo linux Yes, it does work if i dont use threads. It also works if I add  sleep 1; to the subroutine test before printing the info. Hope this helps!

I didn't see a join() anywhere in your app (which may explain your ability to get a result w/ sleep 1). After you spawn your threads, you need to explicitly wait for them all to complete via:

$thr->join();
$thr2->join();
...etc...
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Otherwise the main thread will just exit, which may cause the child threads to get prematurely killed.

when testing I just add

my thr = threads->create(\&test,"host","string","2"); 
my thr2 = threads->create(\&test,"newhost","string","2");
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to the code and no matter how many threads I add the last one is the only one to return data. I dont know what else to add if you require anything more please tell me. thanks.

when testing I just add

my thr  = threads->create(\&test,"host","string","2");
my thr2 = threads->create(\&test,"newhost","string","2");
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to the code and no matter how many threads I add the last one is the only one to return data. I dont know what else to add if you require anything more please tell me. thanks.

I think you may be out of luck with using this module and threads together, From a cursory browse of the XS component of this module, it seems to make extensive use of static data areas. If my reading is correct, the module will be trying to reuse those same static C variables in conjunction with all your threads, and that obviously isn't going to work.

However, from a cursory reading of the docs, you probably don't need to be using threading or forks for this. The module has built in asynchronous capabilities. You simply pass a callback address on each (f)get(next)() of set() call and then enter it's event loop &SNMP::MainLoop([<timeout>, [<callback>]]) and your queries will call your code when the results arrive.

While searching on the internet I found many references to this solution yet no example that implements it or good documentation. If you know of any please post the links. Thank you

If you are issuing identical requests to multiple hosts, you can just use SNMP::Multi and forget about the details :)

If not, take a look at the source for SNMP::Multi, in particular the request() & execute() subs, to see what needs to be done. Basically, loop over the hosts issuing your get()s and passing a callback, (closures would be good here), and then enter the MainLoop and allow it to go to work.

Of course, there's a bit more to it that that with timeouts, retries and collating the information returned.

---

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I'm doing a walk on a each device for example to get the interface information on over 1000 devices at the same time ( it depends on whats needed by the engineer). I decided to leave the threads implementation because of the huge overhead and im currently using fork to initiate about 10 process to start each session with each device and its still not fast enough. I would appreciate if you go into more detail about your implementation. Thanks!

You will need to read the Net::SNMP documentation several times before it sinks in properly, I found. Here's a quick example of how to get the IfInOctets and IfOutOctets for interface number 1 on multiple hosts in one hit. It's not much different from the examples in the docs, though:


use warnings;
use strict;
use Net::SNMP;

my $community="public";    # community string for devices
my $interface_number=1;    # interface number to poll
my @ip_addresses=("192.168.5.242","192.168.11.34");
# Queue up a request to each host.
foreach (@ip_addresses)
{
        my ($session,$error)=Net::SNMP->session(-hostname=>"$_",
            -nonblocking=>1,
            -community=>"$community",
            -timeout=>2,
            -retries=>3,
            );
    if (defined($session))
    {
        my $in_oid=".1.3.6.1.2.1.2.2.1.10."."$interface_number";    # 
+OIDs to poll.
        my $out_oid=".1.3.6.1.2.1.2.2.1.16."."$interface_number";
        my $uptime_oid=".1.3.6.1.2.1.1.3.0";
        my @oids=($in_oid,$out_oid,$uptime_oid);
        my $result=$session->get_request(
            -varbindlist=>\@oids,
            callback=>[\&reply,$interface_number,$_]
            );
    }
    else
    {
        print "Session not defined! $error\n";
    }
}
# All requests are queued. Now dispatch them.
snmp_dispatcher();
exit;
# Sub "reply" is executed for each response from remote hosts.
sub reply
{
    my $obj=shift;
    my $interface=shift;
    my $ip_address=shift;
    if (!defined($obj->var_bind_list))
    {
        warn "$ip_address SNMP Error.",$obj->error(),"\n";
        return;
    }
    my $in_oid=".1.3.6.1.2.1.2.2.1.10."."$interface";
    my $out_oid =".1.3.6.1.2.1.2.2.1.16."."$interface";
    my $uptime_oid=".1.3.6.1.2.1.1.3.0";
    my $uptime=$obj->var_bind_list->{$uptime_oid};
    my $in=$obj->var_bind_list->{$in_oid};
    my $out=$obj->var_bind_list->{$out_oid};
    print "$ip_address interface number $interface bytes in: $in bytes
+ out: $out Uptime $uptime\n";
}
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Keep these things in mind when designing this:
In non-blocking mode, it will queue all requests without actually dispatching them until you execute the snmp_dispatcher.
At that point, your program will block until all requests have been finished.
Each time a response is recieved, it will call the 'reply' subroutine.
You only get control back to the main program after all requests have either completed or timed out.
Good luck.