perl function endservent

The endservent function in Perl is used to free system resources associated with the services file that were previously allocated by the getservent function. Here's an example of how to use endservent:

use POSIX qw(getservent endservent);

my $service_name = 'http';
my $service_port;

while (my ($name, $aliases, $port, $proto) = getservent()) {
  if ($name eq $service_name) {
    $service_port = $port;
    last;
  }
}

endservent();

print "Port number for $service_name: $service_port\n";

In this example, the getservent function is used in a loop to iterate over each entry in the system's services file. For each service entry, the script checks if its name matches the value of $service_name. If a matching service is found, its port number is stored in the $service_port variable. The loop is then exited using the last keyword.

After the loop has finished, the endservent function is called to free system resources associated with the services file. Finally, the script prints the port number corresponding to the service specified by $service_name.

The endservent function is typically used after calling getservent, getservbyname, or getservbyport to ensure that system resources are properly freed. If you forget to call endservent, it may cause resource leaks or other issues.