APC 是 PHP 的效能優化的擴充模組

啟動 Apache 伺服器
# service httpd start
# chkconfig httpd on

APC 有 rpm 套件可以安裝，但是安裝前有很多相依的套件必須先安裝好
安裝 php-pear、php-devel、httpd-devel
# yum install php-pear php-devel httpd-devel

整個開發工具都要安裝，過程要有一段時間
# yum groupinstall 'Development Tools'

整個開發的函式庫也要安裝，過程要有一段時間
# yum groupinstall 'Development Libraries'

用 PECL，PECL 是專門用來安裝 PHP 的擴充模組來安裝 APC

# pecl install apc

downloading APC-3.0.18.tgz ...
Starting to download APC-3.0.18.tgz (115,957 bytes)
....done: 115,957 bytes
47 source files, building
running: phpize
Configuring for:
PHP Api Version:         20041225
Zend Module Api No:      20060613
Zend Extension Api No:   220060519
1. Use apxs to set compile flags (if using APC with Apache)? : yes

1-1, 'all', 'abort', or Enter to continue:  ← Enter

.
.
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Build process completed successfully
Installing '/usr/lib/php/modules/apc.so'
install ok: channel://pecl.php.net/APC-3.0.18
configuration option "php_ini" is not set to php.ini location
You should add "extension=apc.so" to php.ini

安裝好 PAC 之後要真正讓 APC 生效還必須產生 apc.ini 這個設定檔，至少要有以下這三行內容
# vi /etc/php.d/apc.ini

extension=apc.so
apc.enabled=1
apc.shm_size=30

重新啟動 apache
# service httpd restart

測試一下
# vi /var/www/html/info.php

<?php phpinfo(); ?>

http://192.168.1.103/info.php

如下圖，果然 APC 已經安裝好生效了!

SimpleXML
http://tw2.php.net/simplexml