Perl setprotoent Function

Description

This function should be called before the first call to getprotoent. The STAYOPEN argument is optional and unused on most systems. As getprotoent() retriews the information for the next line in the protocol database, then setprotoent sets (or resets) the enumeration to the beginning of the set of host entries.

Syntax

Following is the simple syntax for this function −

setprotoent STAYOPEN

Return Value

This function does not return any value.

Example

Following is the example code showing its basic usage −

#!/usr/bin/perl

while(($name, $aliases, $protocol_number) = getprotoent()) {
   print "Name = $name\n";
   print "Aliases = $aliases\n";
   print "Protocol Number = $protocol_number\n";
}

setprotoent(1); # Rewind the database.

while(($name, $aliases, $protocol_number) = getprotoent()) {
   print "Name = $name\n";
   print "Aliases = $aliases\n";
   print "Protocol Number = $protocol_number\n";
}
endprotoent();  # Closes the database

When above code is executed, it produces the following result −

Name = ip
Aliases = IP
Protocol Number = 0
Name = hopopt
Aliases = HOPOPT
Protocol Number = 0
Name = icmp
Aliases = ICMP
Protocol Number = 1
Name = igmp
Aliases = IGMP
Protocol Number = 2
Name = ggp
Aliases = GGP
Protocol Number = 3
Name = ipencap
Aliases = IP-ENCAP
Protocol Number = 4
Name = st
Aliases = ST
Protocol Number = 5
.
.
.
Name = rsvp-e2e-ignore
Aliases = RSVP-E2E-IGNORE
Protocol Number = 134
Name = udplite
Aliases = UDPLite
Protocol Number = 136
Name = mpls-in-ip
Aliases = MPLS-in-IP
Protocol Number = 137
Name = manet
Aliases = manet
Protocol Number = 138
Name = hip
Aliases = HIP
Protocol Number = 139
Name = shim6
Aliases = Shim6
Protocol Number = 140