fp_ioctl Kernel Service

Purpose

Issues a control command to an open device or file.

Syntax

#include <sys/types.h>
#include <sys/errno.h>

int fp_ioctl (fp, cmd, arg, ext) struct file * fp; unsigned longcmd; caddr_targ; intext;

Parameters

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.

Description

The fp_ioctl kernel service is an internal interface to the function provided by the ioctl subroutine.

Execution Environment

The fp_ioctl kernel service can be called from the process environment only.

Return Values

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.