fp_ioctl Kernel Service

Purpose

Issues a control command to an open device or file.

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

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

Table 1. Parameters
Item	Description
`fp`	Specifies a file structure that is returned by the `fp_open` or `fp_opendev` kernel service.
`cmd`	Specifies the specific control command requested.
`arg`	Indicates the data that is required for the command.
`ext`	Specifies an extension argument that is 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.

Table 2. 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.