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AIX Version 4 Files Reference

dials Special File


Provides access to the dials.


The dials special file is the application interface to the dials. It allows the applications to receive operator input from the dials and to set the granularity of the dials.


Standard configuration methods are provided for the dials special file. The user cannot enter configurable attributes by way of the command line.

Usage Considerations


An open subroutine call specifying the dials 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 dials special file. All dials inputs are flushed following an open call until an input ring is established.

read and write

The dials special file does not support read or write subroutine calls. Input data is obtained from the dials via the input ring. The read and write subroutine calls behave the same as read or write to /dev/null. See "LFT Input Ring" in AIX Version 4.3 Kernel Extensions and Device Support Programming Concepts for how to use the input ring.


The dials special file supports the following ioctl operations:

IOCINFO Returns the devinfo structure.
DIALREGRING Registers input ring.
DIALRFLUSH Flushes input ring.
DIALSETGRAND Sets dial granularity.

Error Codes

The 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 I/O error.
ENOMEM Indicates insufficient memory for required paging operation.
ENOSPC Indicates insufficient file system or paging space.
EINVAL Indicates invalid argument specified.
EINTR Indicates request interrupted by signal.
EPERM Indicates a permanent error occurred.
EBUSY Indicates device busy.
ENXIO Indicates unsupported device number.
ENODEV Indicates unsupported device or device type mismatch.

Implementation Specifics

The dials special file is part of Base Operating System (BOS) Runtime.


/usr/include/sys/inputdd.h Contains declarations for ioctl commands and input ring report format.

Related Information

The GIO special file, kbd special file, lpfk special file, mouse special file, tablet special file.

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

Special Files Overview.

Graphic Input Devices Subsystem Overview in AIX Version 4.3 Kernel Extensions and Device Support Programming Concepts.

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