Help for tcpinfo

hi everyone,
now I am trying to use $tcpinfo_rtt in the nginx.conf, but it can not be
recognized.

below is my envioroment. and when I built nginx 1.6.1, it said "checking
for TCP_INFO … not found "

[lichuanhui@yptest01v ~/nginx-1.6.1]$ cat /etc/redhat-release
CentOS release 5.4 (Final)
[lichuanhui@yptest01v ~/nginx-1.6.1]$ uname -a
Linux yptest01v.add.corp.qihoo.net 2.6.18-164.el5xen #1 SMP Thu Sep 3
04:03:03 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

2014-09-11

mylich119

On Thursday 11 September 2014 15:09:00 mylich119 wrote:

Linux yptest01v.add.corp.qihoo.net 2.6.18-164.el5xen #1 SMP Thu Sep 3
04:03:03 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

That’s what usually happens when you’re using ancient OS.
If I’m not mistaken, you need glibc 2.7 or later.

wbr, Valentin V. Bartenev