Can't call method "recv" on an undefined value

randall_c has asked for the wisdom of the Perl Monks concerning the following question:

I am looking for some help with a perl script I a have written to receive data on a designated port. If there is another way to code this to listen and receive messages, I would appreciate that too. When I run the script I created, I get the following error:

Can't call method "recv" on an undefined value at W:\Developers\Randal
+l_c\Working\sms_interface_server_receive.pl line 84.
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Here is the code form the perl script:

 # Server Program
use IO::Socket;
print ">> Server Program <<\n";
# Create a new socket
my $socket=new IO::Socket::INET(LocalHost => '172.17.8.201', LocalPort
+=>2003,Proto=>'tcp'); print "Connection to the socket was successful.
+\n"; # Keep receiving messages from client my $def_msg="\nWaiting to 
+receive message from client.....\n"; my $text =''; my $varlength = 24
+;
while(1)
{
    
    $socket->recv($text,'24');
    if($text ne '')
    {
        print "\nReceived message '", $text,"'\n";
    }
    # If client message is empty exit
    else
    {
        print "Cilent has exited!";
        exit 1;
    }
}

}
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Re: Can't call method "recv" on an undefined value by ikegami (Patriarch) on Feb 19, 2007 at 18:32 UTC
Printing "Connection to the socket was successful" doesn't make it so. You're getting the error because `$socket` is not defined (like the error message says), and it's undefined because your `new` failed. Use the following construct to get a more meaningful error message: `my $socket = IO::Socket::INET->new(...) or die("Unable to create socket: $!\n");` [download] If you're trying to create a server socket, you need to specify a `Listen` argument. Furthermore, you should probably omit `LocalHost`. If you're trying to create a client socket, you need to specify a `PeerAddr` and the `PeerPort` argument, and you should remove `LocalHost` and `LocalPort`.	[reply] [d/l] [select]

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Re: Can't call method "recv" on an undefined value
by ikegami (Patriarch) on Feb 19, 2007 at 18:32 UTC

Printing "Connection to the socket was successful" doesn't make it so. You're getting the error because $socket is not defined (like the error message says), and it's undefined because your new failed. Use the following construct to get a more meaningful error message:

my $socket = IO::Socket::INET->new(...)
   or die("Unable to create socket: $!\n");
[download]

If you're trying to create a server socket, you need to specify a Listen argument. Furthermore, you should probably omit LocalHost.

If you're trying to create a client socket, you need to specify a PeerAddr and the PeerPort argument, and you should remove LocalHost and LocalPort.

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