perl function getsockopt

The getsockopt function is a built-in Perl function that is used to retrieve socket options. It takes a socket file descriptor, a level, and an option name as its arguments and returns the value of the specified option.

Here's an example that demonstrates how to use getsockopt:

#!/usr/bin/perl

use strict;
use warnings;
use Socket;

# Create a socket
socket(SOCK, PF_INET, SOCK_STREAM, getprotobyname('tcp'));

# Get the value of the SO_SNDBUF option
my $send_buffer_size = getsockopt(SOCK, SOL_SOCKET, SO_SNDBUF);

# Get the value of the SO_RCVBUF option
my $recv_buffer_size = getsockopt(SOCK, SOL_SOCKET, SO_RCVBUF);

# Print the buffer sizes
print "Send Buffer Size: $send_buffer_size\n";
print "Receive Buffer Size: $recv_buffer_size\n";

# Close the socket
close(SOCK);

In this example, we create a socket using the socket function and then call getsockopt to retrieve the values of the SO_SNDBUF and SO_RCVBUF options. We assign the values to the variables $send_buffer_size and $recv_buffer_size, respectively, and then print them to the console.

Note that we need to include the Socket module in order to use the SOL_SOCKET, SO_SNDBUF, and SO_RCVBUF constants, which are used to specify the option level and names.