Perl getsockopt()函数

perl getsockopt()函数，getsockopt()函数学习例子，getsockopt()函数实例代码，getsockopt()函数在线教程等

语法

getsockopt SOCKET, LEVEL, OPTNAME

定义和用法

获取套接字选项SOCKET套接字实现的选项OPTNAME级别LEVEL。在下表中给出一些的样例值用于OPTNAME一个套接字级别

OPTNAME 	Result SO_DEBUG 	Get status of recording of debugging information
SO_REUSEADDR 	Get status of local address reuse
SO_KEEPALIVE 	Get status of keep connections alive
SO_DONTROUTE 	Get status of routing bypass for outgoing messages
SO_LINGER 	Get status of linger on close if data is present
SO_BROADCAST 	Get status of permission to transmit broadcast messages
SO_OOBINLINE 	Get status of out-of-band data in band
SO_SNDBUF 	Get buffer size for output
SO_RCVBUF 	Get buffer size for input
SO_TYPE 	Get the type of the socket
SO_ERROR 	Get and clear error on the socket
TCP_NODELAY     To disable the Nagle buffering algorithm.

到底在包中的字符串是什么，取决于LEVEL和OPTNAME， 详细信息，请咨询您的系统文档。

返回值

• 在标量上下文的错误返回undef，否则选项值。

实例

试试下面的例子：如果使用Nagle算法上打开一个socket，这将检查：

#!/usr/bin/perl
#by www.gitbook.net

use Socket qw(:all);

defined(my $tcp = getprotobyname("tcp"))
   or die "Could not determine the protocol number for tcp";
# my $tcp = IPPROTO_TCP; # Alternative

my $packed = getsockopt($socket, $tcp, TCP_NODELAY)
   or die "Could not query TCP_NODELAY socket option: $!";
my $nodelay = unpack("I", $packed);

print "Nagle's algorithm is turned ", $nodelay ? "off\n" : "on\n";