Perl getprotoent 函数

描述

此函数返回有效协议列表中的下一个条目：($name, $aliases, $protocol_number)

句法

以下是该函数的简单语法 -

getprotoent

返回值

该函数在错误时返回 undef，否则在标量上下文中返回协议编号，并在列表上下文中返回错误协议记录（名称、别名、协议编号）的空列表。

例子

以下是显示其基本用法的示例代码 -

#!/usr/bin/perl

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

执行上述代码时，会产生以下结果 -

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 = 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