Issues a control command to an open device or file.
Item | Description |
---|---|
fp | Points to a file structure returned by the fp_open or fp_opendev kernel service. |
cmd | Specifies the specific control command requested. |
arg | Indicates the data required for the command. |
ext | Specifies an extension argument required by some device drivers. Its content, form, and use are determined by the individual driver. |
The fp_ioctl kernel service is an internal interface to the function provided by the ioctl subroutine.
The fp_ioctl kernel service can be called from the process environment only.
Item | Description |
---|---|
0 | Indicates a successful operation. |
If an error occurs, one of the values from the /usr/include/sys/errno.h file is returned. The ioctl subroutine contains valid errno values.