perl function endprotoent

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

use POSIX qw(getprotoent endprotoent);

my $protocol_name = 'tcp';
my $protocol_number;

while (my ($name, $aliases, $number) = getprotoent()) {
  if ($name eq $protocol_name) {
    $protocol_number = $number;
    last;
  }
}

endprotoent();

print "Protocol number for $protocol_name: $protocol_number\n";

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

After the loop has finished, the endprotoent function is called to free system resources associated with the protocol file. Finally, the script prints the number corresponding to the protocol specified by $protocol_name.

The endprotoent function is typically used after calling getprotoent, getprotobynumber, or getprotobyname to ensure that system resources are properly freed. If you forget to call endprotoent, it may cause resource leaks or other issues.