由于前文“Centos 7.2 yum安装php7”中升级了php到php7，导致之前可以正常使用的phpmyadmin、memcache等无法继续使用，需要重新编译安装，memcache目前未找到有效的解决方法，只好重新安装memcached来替代之前的memcache。此处介绍memcached的安装编译。
1、试图按以前的经验，直接升级memcache：
[root@iZ23d ~]# pecl upgrade memcache
bash: pecl: command not found...
根据这边的提示，需要安装相应的 yum install php-devel php-pear httpd-devel
[root@iZ23d ~]# yum install php70w-devel php70w-pear php70w-httpd-devel
Loaded plugins: langpacks
Repository base is listed more than once in the configuration
Repository updates is listed more than once in the configuration
。。。。 【其中省略】
Warning: RPMDB altered outside of yum.
Installing : php70w-process-7.0.0-1.w7.x86_64 1/4
Installing : php70w-xml-7.0.0-1.w7.x86_64 2/4
Installing : 1:php70w-pear-1.10.1-1.w7.noarch 3/4
Installing : php70w-devel-7.0.0-1.w7.x86_64 4/4
Verifying : php70w-devel-7.0.0-1.w7.x86_64 1/4
Verifying : php70w-xml-7.0.0-1.w7.x86_64 2/4
Verifying : 1:php70w-pear-1.10.1-1.w7.noarch 3/4
Verifying : php70w-process-7.0.0-1.w7.x86_64 4/4
Installed:
php70w-devel.x86_64 0:7.0.0-1.w7 php70w-pear.noarch 1:1.10.1-1.w7
Dependency Installed:
php70w-process.x86_64 0:7.0.0-1.w7 php70w-xml.x86_64 0:7.0.0-1.w7
Complete!
继续按偷懒的方法升级：
[root@iZ23d ~]# pecl upgrade memcache
downloading memcache-2.2.7.tgz ...
Starting to download memcache-2.2.7.tgz (36,459 bytes)
.....done: 36,459 bytes
11 source files, building
running: phpize
Configuring for:
PHP Api Version: 20151012
Zend Module Api No: 20151012
Zend Extension Api No: 320151012
。。。 【其中省略】 config.status: executing libtool commands
running: make
/bin/sh /var/tmp/pear-build-rootEb5cjP/memcache-2.2.7/libtool --mode=compile cc -I/usr/include/php -I. -I/var/tmp/memcache -DPHP_ATOM_INC -I/var/tmp/pear-build-rootEb5cjP/memcache-2.2.7/include -I/var/tmp/pear-build-rootEb5cjP/memcache-2.2.7/main -I/var/tmp/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /var/tmp/memcache/memcache.c -o memcache.lo
libtool: compile: cc -I/usr/include/php -I. -I/var/tmp/memcache -DPHP_ATOM_INC -I/var/tmp/pear-build-rootEb5cjP/memcache-2.2.7/include -I/var/tmp/pear-build-rootEb5cjP/memcache-2.2.7/main -I/var/tmp/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /var/tmp/memcache/memcache.c -fPIC -DPIC -o .libs/memcache.o
/var/tmp/memcache/memcache.c:40:40: fatal error: ext/standard/php_smart_str.h: No such file or directory
#include "ext/standard/php_smart_str.h"
^
compilation terminated.
make: *** [memcache.lo] Error 1
ERROR: `make' failed
说明升级失败，缺乏 php_smart_str.h 文件，查看是否有相应文件的源文件：
[root@iZ23d ~]# find / -name php_smart_str.h
/root/php-5.4.16/ext/standard/php_smart_str.h
以上说明 php5中有相应的文件，但是已经下载并解压的 php7源安装包中却没有相应文件，而这边前人的经验也表面，可能是Php7本身的某些扩展未做到位。
而根据这边的说法，之前版本的php中的 php_smart_str.h 在 php7 中已经改名为 php_smart_string.h ；
查看相应的文件：
[root@iZ23d ~]# find / -name php_smart_string.h
/usr/include/php-zts/php/ext/standard/php_smart_string.h
/usr/include/php/ext/standard/php_smart_string.h
/root/php-7.0.1RC1/ext/standard/php_smart_string.h
的确有相应的文件，但是，尝试把相应的文件拷贝一份并命名为相应的 php_smart_str.h 后，重新升级编译安装，并不能解决问题。
在github和stackoverflow均看到此问题暂时没有解决方案，只能等Php7完善。不得已，只能放弃。
在寻找memcache解决方案的过程中，发现memcached碰到的问题几乎和memcache一样，但是，却从 stackoverflow 找到一个可行的 memcached 安装方法，并证实有效。下面是具体的过程。
第一步，直接git clone：
[root@iZ23d ~]# git clone https://gith
Cloning into 'php-memcached'...
remote: Counting objects: 2965, done.
remote: Total 2965 (delta 0), reused 0 (delta 0), pack-reused 2965
Receiving objects: 100% (2965/2965), 931.47 KiB | 8.00 KiB/s, done.
Resolving deltas: 100% (1774/1774), done.
第二步：
[root@iZ23d ~]# cd php-memcached
[root@iZ23d php-memcached]# git checkout php7
Branch php7 set up to track remote branch php7 from origin.
Switched to a new branch 'php7'
第三步：
[root@iZ23d php-memcached]# phpize
Configuring for:
PHP Api Version: 20151012
Zend Module Api No: 20151012
Zend Extension Api No: 320151012
第四步：configure
[root@iZ23d php-memcached]# ./configure
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
。。。 【省略部分】
checking for memcached session support... enabled
checking for memcached igbinary support... disabled
checking for memcached msgpack support... disabled
checking for libmemcached location... configure: error: memcached support requires libmemcached. Use --with-libmemcached-dir=<DIR> to specify the prefix where libmemcached headers and library are located
第五步：根据错误提示，重新 configure ：
先找到相应文件：
[root@iZ23d php-memcached]# find / -name libmemcached
/usr/local/libmemcached
/usr/local/libmemcached/include/libmemcached
/root/libmemcached-1.0.18/libmemcached
[root@iZ23d php-memcached]# ./configure --with-libmemcached-dir=/usr/local/libmemcached
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for a sed that does not truncate output... /usr/bin/sed
checking for cc... cc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
。。。
checking for sasl/sasl.h... yes
checking whether libmemcached supports sasl... no
configure: error: no, libmemcached sasl support is not enabled. Run configure with --disable-memcached-sasl to disable this check
再根据新提示，继续：
[root@iZ23d php-memcached]# ./configure --with-libmemcached-dir=/usr/local/libmemcached --disable-memcached-sasl
checking for grep that handles long lines and -e... /usr/bin/grep
。。。
configure: creating ./config.status
config.status: creating config.h
config.status: executing libtool commands
终于未出现错误提示！
第六步，make：
[root@iZ23d php-memcached]# make
/bin/sh /root/php-memcached/libtool --mode=compile cc -I/usr/include/php -I. -I/root/php-memcached -DPHP_ATOM_INC -I/root/php-memcached/include -I/root/php-memcached/main -I/root/php-memcached -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -I/usr/local/libmemcached/include -DHAVE_CONFIG_H -g -O2 -c /root/php-memcached/php_memcached.c -o php_memcached.lo
libtool: compile: cc -I/usr/include/php -I. -I/root/php-memcached -DPHP_ATOM_INC -I/root/php-memcached/include -I/root/php-memcached/main -I/root/php-memcached -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -I/usr/local/libmemcached/include -DHAVE_CONFIG_H -g -O2 -c /root/php-memcached/php_memcached.c -fPIC -DPIC -o .libs/php_memcached.o
。。。。。 【省略部分】
libtool: install: cp ./.libs/memcached.so /root/php-memcached/modules/memcached.so
libtool: install: cp ./.libs/memcached.lai /root/php-memcached/modules/memcached.la
libtool: finish: PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/usr/java/jdk1.8.0_45:/root/bin:/sbin" ldconfig -n /root/php-memcached/modules
----------------------------------------------------------------------
Libraries have been installed in:
/root/php-memcached/modules
If you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the `-LLIBDIR'
flag during linking and do at least one of the following:
- add LIBDIR to the `LD_LIBRARY_PATH' environment variable
during execution
- add LIBDIR to the `LD_RUN_PATH' environment variable
during linking
- use the `-Wl,-rpath -Wl,LIBDIR' linker flag
- have your system administrator add LIBDIR to `/etc/ld.so.conf'
See any operating system documentation about shared libraries for
more information, such as the ld(1) and ld.so(8) manual pages.
----------------------------------------------------------------------
Build complete.
Don't forget to run 'make test'.
根据提示，继续 make test ：
[root@iZ23d php-memcached]# make test
Build complete.
Don't forget to run 'make test'.
。。。【省略部分】
Thank you for helping to make PHP better.
第七部， make install ：
[root@iZ23d php-memcached]# make install
Installing shared extensions: /usr/lib64/php/modules/
第八步， 重启 Apache，在/etc/php.ini 的最后添加 extension="memcached.so"，保存退出，重启Apache ：
[root@iZ23d php-memcached]# cd ..
[root@iZ23d ~]# systemctl restart httpd.service
第九步，验证检查 memcached 安装结果：
查看 php 版本，看看会否报错，若报错，说明 memcached 安装错误，否则多半表示安装成功：
[root@iZ23d ~]# php -v
PHP 7.0.0 (cli)(built: Dec 2 2015 20:42:32) ( NTS )
Copyright (c) 1997-2015 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2015 Zend Technologies
以上结果说明，memcached安装成功。
查看phpinfo，已经显示memcached的扩展内容，内容展示如下：
memcached
| memcached support | enabled |
|---|---|
| Version | 2.2.0 |
| libmemcached version | 1.0.18 |
| SASL support | no |
| Session support | yes |
| igbinary support | no |
| json support | no |
| msgpack support | no |
| Directive | Local Value | Master Value |
|---|---|---|
| memcached.compression_factor | 1.3 | 1.3 |
| memcached.compression_threshold | 2000 | 2000 |
| memcached.compression_type | fastlz | fastlz |
| memcached.serializer | php | php |
| memcached.sess_binary | 0 | 0 |
| memcached.sess_connect_timeout | 1000 | 1000 |
| memcached.sess_consistent_hash | 0 | 0 |
| memcached.sess_lock_expire | 0 | 0 |
| memcached.sess_lock_max_wait | 0 | 0 |
| memcached.sess_lock_wait | 150000 | 150000 |
| memcached.sess_locking | 1 | 1 |
| memcached.sess_number_of_replicas | 0 | 0 |
| memcached.sess_prefix | memc.sess.key. | memc.sess.key. |
| memcached.sess_randomize_replica_read | 0 | 0 |
| memcached.sess_remove_failed | 0 | 0 |
| memcached.store_retry_count | 2 | 2 |
再次证明 memcached 安装成功！
第十步，启动 memcached ：
[root@iZ23d ~]# systemctl start memcached.service
查看状态：
[root@iZ23d ~]# systemctl status memcached.service
● memcached.service - Memcached
Loaded: loaded (/usr/lib/systemd/system/memcached.service; disabled; vendor preset: disabled)
Active: active (running) since Mon 2015-12-21 19:55:07 CST; 14s ago
Main PID: 1426 (memcached)
CGroup: /system.slice/memcached.service
└─1426 /usr/bin/memcached -u memcached -p 11211 -m 64 -c 1024
Dec 21 19:55:07 iZ23d2e6hoqZ systemd[1]: Started Memcached.
Dec 21 19:55:07 iZ23d2e6hoqZ systemd[1]: Starting Memcached...
设置开机启动：
[root@iZ23d ~]# systemctl enable memcached.service
Created symlink from /etc/systemd/system/multi-user.target.wants/memcached.service to /usr/lib/systemd/system/memcached.service.
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