Kontron KTAM3874-pITX - Manual (Page 270)

KTD-S0057-I Page 266 Linux® Programming Examples (DebianTM)
KTAM3874/pITX Software Guide
#include <linux/limits.h>
#include "fifo.h"
int main (void)
{
int fifo_rd, fifo_wr, n;
struct pollfd pfd;
static char buff_rd [RD_SIZE];
static char buff_wr [WR_SIZE];
if ((fifo_rd = open (root_wr, O_RDONLY | O_NDELAY)) < 0 || (fifo_wr = open (root_rd, O_WRONLY)) < 0)
ERROR;
while (1)
{
write (fileno (stdout), CMD_STR, strlen (CMD_STR));
memset (buff_wr, 0, WR_SIZE);
memset (buff_rd, 0, RD_SIZE);
n = read (fileno (stdin), buff_wr, WR_SIZE);
write (fifo_wr, buff_wr, n);
if (! strncasecmp (buff_wr, CMD_EXIT, CMD_SIZE))
break;
pfd.fd = fifo_rd;
pfd.events = POLLIN;
if (poll (&pfd, 1, POLL_TIME) > 0) /* wait 5 milliseconds */
{
write (fileno (stderr), ACK_APP, strlen (ACK_APP));
while ((n = read (fifo_rd, buff_rd, RD_SIZE)) > 0)
write (fileno (stderr), buff_rd, n);
}
else
write (fileno (stderr), TIMEOUT_STR, strlen (TIMEOUT_STR));
}
close (fifo_rd);
close (fifo_wr);
return 0;
}
First open a terminal window, type
su (password root ) or sudo -i (password ktam3874 ), change to your
target directory with the server application and start the server program with ' ./server '. Thereafter open a
second new terminal window, go to your target directory with the client application and run this program
with '
./client ' (not as root).
Both samples are based on practical experience and aimed at simple and quick implementation of inter-
process communication, therefore only watchdog and GPIO functionality are implemented.
Command table:
wdio on 30 Activate the watchdog with timeout of 30 seconds
wdio off Disable the watchdog
wdio trig Trigger the watchdog