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Files Reference

GIO Special File


Provides access to the graphics I/O (GIO) adapter.


The GIO special file is the application interface to the GIO adapter. The GIO special file provides applications with the ability to determine what I/O devices are attached to the GIO adapter.


Standard configuration methods are provided for the GIO special file. User configurable attributes for the GIO special file do not exist.

Usage Considerations

The open subroutine call specifying the GIO special file is processed normally except that the Oflag and Mode parameters are ignored. An open request is rejected if the special file is already opened or if a kernel extension attempts to open the GIO special file.

Calls to the read and write routines behave as if the call was made to the /dev/null file.

The GIO special file supports the following functions with ioctls:

IOCINFO Returns the devinfo structure.
GIOQUERYID Returns the identifier of device connected to the GIO adapter.

Error Codes

The following error codes can be found in the /usr/include/sys/errno.h file:

EFAULT Indicates insufficient authority to access address or invalid address.
EIO Indicates an I/O error.
ENOMEM Indicates insufficient memory for required paging operation.
ENOSPC Indicates insufficient file system or paging space.
EINVAL Indicates that an invalid argument was specified.
EINTR Indicates a request interrupted by signal.
EPERM Indicates a permanent error occurred.
EBUSY Indicates the device is busy.
ENXIO Indicates an unsupported device number.
ENODEV Indicates an unsupported device or device type mismatch occurred.


/usr/include/sys/inputdd.h Contains the ioctl commands.

Related Information

The close subroutine, ioctl subroutine, open subroutine, read subroutine, write subroutine.

The dials special file, lpfk special file.

Special Files Overview .

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