PHP supports the direct io functions as described in the Posix Standard (Section 6) for performing I/O functions at a lower level than the C-Language stream I/O functions (fopen(), fread(),..). The use of the DIO functions should be considered only when direct control of a device is needed. In all other cases, the standard filesystem functions are more than adequate.
Note: 本扩展已被移动到 » PECL 库中且自以下版本起不再被绑定到 PHP 中：5.1.0.
This extension is only available on Windows Platforms as of PHP 5.0.0
To get these functions to work, you have to configure PHP with --enable-dio.
以下常量由本扩展模块定义，因此只有在本扩展模块被编译到 PHP 中，或者在运行时被动态加载后才有效。
本扩展模块在 php.ini 中未定义任何配置选项。
One resource type is defined by this extension: a file descriptor returned by dio_open().