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Files Reference

tablet Special File


Provides access to the tablet.


The tablet special file is the application interface to the tablet. It provides the applications with the capability of receiving input from the tablet and it allows the application to change the sampling rate, dead zones, origin, resolution, and conversion mode.


There are no user commands to change the configuration of the tablet device. Applications may use ioctl commands to modify the configuration but these modifications are effective only until the tablet is closed.

Usage Considerations

The open subroutine call specifying the tablet special file is processed normally except that the Oflag and Mode parameters are ignored. The open request is rejected if the special file is already opened or if a kernel extension attempts to open the special file. All tablet inputs are flushed following an open subroutine call until an input ring is established. The tablet device is reset to the default configuration when an open request is made.

The tablet special file does not support the read or write subroutine calls. Instead, input data is obtained from the tablet through the input ring. The read and write subroutine calls behave the same as read or write subroutine calls to the /dev/null file.

The tablet special file supports the following functions with ioctl subroutines:

IOCINFO Returns devinfo structure.
TABCONVERSION Sets tablet conversion mode.
TABDEADZONE Sets tablet dead zones.
TABFLUSH Flushes input ring.
TABORIGIN Sets tablet origin.
TABQUERYID Queries tablet device identifier.
TABREGRING Registers input ring.
TABRESOLUTION Sets resolution.
TABSAMPELRATE Sets sample rate.

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 an I/O error.
ENOMEM Indicates insufficient memory for required paging operation.
ENOSPC Indicates insufficient file system or paging space.
EINVAL Indicates an invalid argument.
EINTR Indicates the request was interrupted by signal.
EPERM Indicates a permanent error occurred.
EBUSY Indicates the device is busy.
ENXIO Indicates an unsupported device number was specified.
ENODEV Indicates an unsupported device or device type mismatch.
EACCES Indicates open is not allowed.


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

Related Information

LFT Input Devices in AIX 5L Version 5.2 Kernel Extensions and Device Support Programming Concepts.

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

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

Special Files Overview .

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