Korenix JetBox5400 series, Руководство пользователя

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Korenix | Programmer’s Guide 57
6-2
Device API
ioctl
Name
ioctl - control device
Library
Standard C Library (libc, -lc)
Synopsis
#include <sys/ioctl.h>
int
ioctl (
int d
,
unsigned long request
,
...
);
Description
The ioctl () system call manipulates the underlying device parameters of special files. In
particular, many operating characteristics of character special files (e.g. terminals) may be
controlled with ioctl () requests. The argument d must be an open file descriptor.
The third argument to ioctl () is traditionally named
char *argp
. Most uses of ioctl (),
however, require the third argument to be a
caddr
_
t
or an
int
.
An ioctl () request has encoded in it whether the argument is an „„in‟‟ argument or „„out‟‟
argument, and the size of the argument
argp
in bytes. Macros and defines used in specifying an
ioctl request are located in the file < sys/ioctl.h >.
Return Values
If an error has occurred, a value of -1 is returned and errno is set to indicate the error.
Please use the desktop Linux’s man page for detailed documentation:
#man ioctl
6-3
RTC
The device node is located at /dev/rtc0. Jetbox supports Linux standard simple RTC control.
You must include <linux/rtc.h>
.