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 is not available on Windows platforms.
One resource type is defined by this extension: a
file descriptor returnded by
dio_open().