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, $protocol_number)
语法
以下是此函数的简单语法 −
getprotoent
返回值
此函数在错误时返回 undef，否则在标量上下文中返回协议号，并在列表上下文中的错误协议记录（名称、别名、协议号）上返回空列表。
示例
以下是显示其基本用法的示例代码 −
#!/usr/bin/perl
while(($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
