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.
注: This extension has been moved to the PECL repository and is no longer bundled with PHP as of PHP 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 中未定义任何设置指令。