Where do you think you were setting IPC_NOWAIT from? try using strict.

use IPC::SysV qw(IPC_PRIVATE IPC_CREAT S_IRWXU IPC_NOWAIT);

$id = msgget(4335, IPC_CREAT | S_IRWXU);

$go = 1;

while($go){

        if(msgrcv($id, $rcvd, 512, 0, IPC_NOWAIT)){
                ($typ_rcvd, $rcvdData) = unpack("l! a*", $rcvd);
                print "Got------>$rcvdData\n";
        }
print "Wait\n";
sleep 1;
}
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