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,..).
These functions are available as part of the standard module, which is always available.
To get these functions to work, you have to configure PHP with --enable-dio.
This extension does not define any configuration directives.
One resource type is defined by this extension: a file descriptor returnded by dio_open().
This extension does not define any constants.