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Direct IO Functions


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.


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


No external libraries are needed to build this extension.


To get these functions to work, you have to configure PHP with --enable-dio.

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

c (integer)
F_DUPFD (integer)
F_GETFD (integer)
F_GETFL (integer)
F_GETLK (integer)
F_GETOWN (integer)
F_RDLCK (integer)
F_SETFL (integer)
F_SETLK (integer)
F_SETLKW (integer)
F_SETOWN (integer)
F_UNLCK (integer)
F_WRLCK (integer)
O_APPEND (integer)
O_ASYNC (integer)
O_CREAT (integer)
O_EXCL (integer)
O_NDELAY (integer)
O_NOCTTY (integer)
O_NONBLOCK (integer)
O_RDONLY (integer)
O_RDWR (integer)
O_SYNC (integer)
O_TRUNC (integer)
O_WRONLY (integer)
S_IRGRP (integer)
S_IROTH (integer)
S_IRUSR (integer)
S_IRWXG (integer)
S_IRWXO (integer)
S_IRWXU (integer)
S_IWGRP (integer)
S_IWOTH (integer)
S_IWUSR (integer)
S_IXGRP (integer)
S_IXOTH (integer)
S_IXUSR (integer)

Runtime Configuration

This extension has no configuration directives defined in php.ini.

Resource Types

One resource type is defined by this extension: a file descriptor returned by dio_open().

Table of Contents

dio_close — Closes the file descriptor given by fd
dio_fcntl — Performs a c library fcntl on fd
dio_open — Opens a new filename with specified permissions of flags and creation permissions of mode
dio_read — Reads bytes from a file descriptor
dio_seek — Seeks to pos on fd from whence
dio_stat — Gets stat information about the file descriptor fd
dio_tcsetattr — Sets terminal attributes and baud rate for a serial port
dio_truncate — Truncates file descriptor fd to offset bytes
dio_write — Writes data to fd with optional truncation at length