extension_loaded — 检查一个扩展是否已经加载

例如：

<?phpif (!extension_loaded(‘gd‘)) {    if (!dl(‘gd.so‘)) {        exit;    }}?>

是否加载  gd 库扩展

Win7->cmd->php -m
[PHP Modules]
bcmath
bz2
calendar
com_dotnet
ctype
curl
date
dom
filter
ftp
gd
hash
iconv
json
libxml
mbstring
mcrypt
mysql
mysqli
odbc
pcre
PDO
pdo_mysql
PDO_ODBC
pdo_sqlite
Reflection
session
SimpleXML
sockets
SPL
SQLite
standard
tokenizer
wddx
xml
xmlreader
xmlwriter
Zend Optimizer
zip
zlib

[Zend Modules]
Zend Extension Manager
Zend Optimizer


D:\Php\phpStudy\php52>

PHP 函数extension_loaded();