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.
Configuration
Standard configuration methods are provided for the dials special file. The user cannot enter configurable attributes by way of the command line.
Usage Considerations
open
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 7.1 Kernel Extensions and Device Support Programming Concepts for how to use the input ring.
ioctl
The dials special file supports the following ioctl operations:
| Item | Description |
|---|---|
| IOCINFO | Returns the devinfo structure. |
| DIALREGRING | Registers input ring. |
| DIALRFLUSH | Flushes input ring. |
| DIALSETGRAND | Sets dial granularity. |
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 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. |
| Item | Description |
|---|---|
| /usr/include/sys/inputdd.h | Contains declarations for ioctl commands and input ring report format. |