Perl setprotoent 函数

说明

在第一次调用 getprotoent 之前应该调用此函数。大多数系统上的 STAYOPEN 参数是可选项，并且不用。当 getprotoent() 检索协议数据库中下一行的信息时，setprotoent 将枚举设置（或重置）为主机条目集合的开头。

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

执行以上代码时，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