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.
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:
| Item | Description |
|---|---|
| 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. |
The error codes can be found in the /usr/include/sys/errno.h file.
| Item | Description |
|---|---|
| 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. |
| Item | Description |
|---|---|
| /usr/include/sys/inputdd.h | Contains declarations for ioctl commands and input ring report format. |