# Direct IO

&reftitle.intro;

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.

&reference.dio.setup; &reference.dio.constants; &reference.dio.reference;