Perl setprotoent 函数
描述
此函数应在第一次调用 getprotoent 之前调用。 STAYOPEN 参数是可选的，在大多数系统上未使用。 当 getprotoent() 重新检索协议数据库中下一行的信息时，setprotoent 将枚举设置（或重置）到主机条目集的开头。
语法
以下是此函数的简单语法 −
setprotoent STAYOPEN
返回值
此函数不返回任何值。
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 = $protocol_number\n";
}
setprotoent(1); # Rewind the database.
while(($name, $aliases, $protocol_number) = getprotoent()) {
print "Name = $name\n";
print "Aliases = $aliases\n";
print "Protocol Number = $protocol_number\n";
}
endprotoent(); # Closes the database
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 = 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
