libmemcache 是C语言的操作memcached的客户端的库
libmemcached 好像应该是服务器端需要的库，实际上不是，ldd memcached :发现和libmemcached并没有关系，下面是libmemcached的README：
Hi!
So what is this? It is a library in C for connectinng to memcached servers
(http://danga.com/memcached/). It is also a collection of utilities designed
to work with memcached.
memcat – Copy the value of a key to standard output
memflush – Flush the contents of your servers.
memrm – Remove a key(s) from the server.
memstat – Dump the stats of your servers to standard output
memslap – Load generation utility (benchmark!)
The utilities are beta quality at this point. The library is in production
in many locations (upwards to 600 nodes). For networks of more then 512
hosts using consistent hashing, you must update the target WHEEL size for
number of hosts * 4 in libmemcached/memcached_constants.h.
Want to contribute? If you write more then three good patches, then I will
just ask you to commit directly to the tree. I am happy to have additional
people work on this project. Please checkout README.FIRST.
You will need a C99 compiler in order to compile this library. Currently we
actively support Linux, MacOSX, FreeBSD, and Solaris. A Windows port is
currently not supported.
If you are looking for answers to your questions please check out the
mailing list at:
http://lists.tangent.org/
Subscribe to the libmemcached mailing list found there.
Cheers,
-Brian Aker
Seattle, WA.
另外，PHP还有一个自己的操作memcache的模块，它是自己实现的，并不依赖C的那个客户端模块